From c9584de5a5d97f1c0d94f2a2d1c304bc0b24cefd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=2E=C2=A0S=2E=20Choi?= <jschoi@jschoi.org>
Date: Tue, 16 Nov 2021 11:49:48 -0500
Subject: [PATCH] proposal-pipe: Add support for @@ and ^^ topics

---
 .../babel-generator/src/generators/types.ts   |   2 +-
 packages/babel-generator/src/index.ts         |   2 +-
 .../input.js                                  |   1 +
 .../options.json                              |   4 +
 .../output.js                                 |   1 +
 .../input.js                                  |   1 +
 .../options.json                              |   4 +
 .../output.js                                 |   1 +
 .../options.json                              |   2 +-
 .../options.json                              |   2 +-
 .../babel-parser/src/parser/expression.js     |  36 ++++-
 packages/babel-parser/src/plugin-utils.js     |   2 +-
 packages/babel-parser/src/tokenizer/index.js  |  38 ++++-
 packages/babel-parser/src/tokenizer/types.js  |  11 +-
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  57 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  62 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  44 +++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  55 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  44 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  52 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  66 ++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   3 +
 .../output.json                               |  54 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   6 +
 .../output.json                               |  81 ++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   6 +
 .../output.json                               |  81 ++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   6 +
 .../output.json                               |  48 ++++++
 .../input.js                                  |   7 +
 .../options.json                              |   7 +
 .../output.json                               | 121 ++++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  89 ++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  49 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../hack-double-at-proposal-division/input.js |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  80 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  80 +++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   6 +
 .../output.json                               |  93 +++++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   6 +
 .../output.json                               |  93 +++++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   7 +
 .../output.json                               |  93 +++++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   7 +
 .../output.json                               |  93 +++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               | 110 +++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               | 106 ++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  61 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  61 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  62 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  62 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  74 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  64 ++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  57 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  73 +++++++++
 .../input.js                                  |   7 +
 .../options.json                              |   3 +
 .../output.json                               | 139 ++++++++++++++++
 .../input.js                                  |   7 +
 .../options.json                              |   3 +
 .../output.json                               | 125 ++++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  47 ++++++
 .../input.js                                  |   4 +
 .../options.json                              |   3 +
 .../output.json                               | 125 ++++++++++++++
 .../input.js                                  |   5 +
 .../options.json                              |   3 +
 .../output.json                               | 152 ++++++++++++++++++
 .../input.js                                  |   5 +
 .../options.json                              |   3 +
 .../output.json                               | 146 +++++++++++++++++
 .../input.js                                  |   4 +
 .../options.json                              |   3 +
 .../output.json                               | 126 +++++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  80 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  80 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  56 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  42 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  35 ++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  59 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  65 ++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  50 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   4 +
 .../input.js                                  |   2 +
 .../options.json                              |   6 +
 .../output.json                               |  69 ++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  31 ++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  40 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  97 +++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  76 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  62 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  60 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  53 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  50 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  41 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  56 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  41 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   7 +
 .../input.js                                  |   7 +
 .../options.json                              |   7 +
 .../output.json                               | 111 +++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  35 ++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  31 ++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  47 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  48 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  38 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   7 +
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   2 +
 .../options.json                              |   3 +
 .../output.json                               | 110 +++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  41 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  41 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  47 ++++++
 .../input.js                                  |   3 +
 .../options.json                              |   3 +
 .../output.json                               |  65 ++++++++
 .../input.js                                  |   3 +
 .../options.json                              |  11 ++
 .../output.json                               |  64 ++++++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  41 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  57 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  62 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  44 +++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  55 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  44 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  52 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  66 ++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   3 +
 .../output.json                               |  54 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   6 +
 .../output.json                               |  81 ++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   6 +
 .../output.json                               |  81 ++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   6 +
 .../output.json                               |  48 ++++++
 .../input.js                                  |   7 +
 .../options.json                              |   7 +
 .../output.json                               | 121 ++++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  89 ++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  49 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  80 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  80 +++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   6 +
 .../output.json                               |  93 +++++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   6 +
 .../output.json                               |  93 +++++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   7 +
 .../output.json                               |  93 +++++++++++
 .../input.js                                  |   3 +
 .../options.json                              |   7 +
 .../output.json                               |  93 +++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               | 110 +++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               | 106 ++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  61 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  61 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  62 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  62 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  74 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  64 ++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  57 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  73 +++++++++
 .../input.js                                  |   7 +
 .../options.json                              |   3 +
 .../output.json                               | 139 ++++++++++++++++
 .../input.js                                  |   7 +
 .../options.json                              |   3 +
 .../output.json                               | 125 ++++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  47 ++++++
 .../input.js                                  |   4 +
 .../options.json                              |   3 +
 .../output.json                               | 125 ++++++++++++++
 .../input.js                                  |   5 +
 .../options.json                              |   3 +
 .../output.json                               | 152 ++++++++++++++++++
 .../input.js                                  |   5 +
 .../options.json                              |   3 +
 .../output.json                               | 146 +++++++++++++++++
 .../input.js                                  |   4 +
 .../options.json                              |   3 +
 .../output.json                               | 126 +++++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  80 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  80 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  56 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  42 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  35 ++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  59 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  65 ++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  50 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   4 +
 .../input.js                                  |   2 +
 .../options.json                              |   6 +
 .../output.json                               |  69 ++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  31 ++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  97 +++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  76 +++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  62 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  60 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  53 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  50 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  41 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  56 +++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  41 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   7 +
 .../input.js                                  |   7 +
 .../options.json                              |   7 +
 .../output.json                               | 111 +++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  35 ++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  31 ++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  47 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  48 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  38 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   7 +
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   2 +
 .../options.json                              |   3 +
 .../output.json                               | 110 +++++++++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  47 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  41 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  41 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  40 +++++
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   4 +
 .../input.js                                  |   1 +
 .../options.json                              |   3 +
 .../output.json                               |  45 ++++++
 .../input.js                                  |   1 +
 .../options.json                              |   4 +
 .../input.js                                  |   3 +
 .../options.json                              |   3 +
 .../output.json                               |  65 ++++++++
 .../input.js                                  |   3 +
 .../options.json                              |  11 ++
 .../output.json                               |  64 ++++++++
 .../input.js                                  |   1 +
 .../options.json                              |  11 ++
 .../output.json                               |  41 +++++
 .../hack-double-at/class-decorator/exec.js    |   8 +
 .../hack-double-at/class-decorator/input.js   |  11 ++
 .../class-decorator/options.json              |   6 +
 .../hack-double-at/class-decorator/output.js  |  27 ++++
 .../hack-double-at/hash-tuple/input.js        |   2 +
 .../hack-double-at/hash-tuple/options.json    |   6 +
 .../hack-double-at/hash-tuple/output.js       |   4 +
 .../test/fixtures/hack-double-at/options.json |   3 +
 .../hack-double-at/pipe-body-identity/exec.js |   3 +
 .../pipe-body-identity/input.js               |   3 +
 .../pipe-body-identity/output.js              |   4 +
 .../pipe-body-with-addition/exec.js           |   3 +
 .../pipe-body-with-addition/input.js          |   3 +
 .../pipe-body-with-addition/output.js         |   4 +
 .../exec.js                                   |   9 ++
 .../input.js                                  |   9 ++
 .../output.js                                 |   8 +
 .../pipe-body-with-arrow-function/exec.js     |   6 +
 .../pipe-body-with-arrow-function/input.js    |   6 +
 .../pipe-body-with-arrow-function/output.js   |   8 +
 .../pipe-body-with-await/exec.js              |  14 ++
 .../pipe-body-with-await/input.js             |  14 ++
 .../pipe-body-with-await/options.json         |   6 +
 .../pipe-body-with-await/output.js            |  13 ++
 .../exec.js                                   |  20 +++
 .../input.js                                  |  20 +++
 .../options.json                              |   6 +
 .../output.js                                 |  19 +++
 .../pipe-body-with-eval/exec.js               |   4 +
 .../pipe-body-with-eval/input.js              |   4 +
 .../pipe-body-with-eval/output.js             |   5 +
 .../pipe-body-with-nested-pipe/exec.js        |   7 +
 .../pipe-body-with-nested-pipe/input.js       |   7 +
 .../pipe-body-with-nested-pipe/output.js      |   4 +
 .../pipe-body-with-object-literal/exec.js     |  10 ++
 .../pipe-body-with-object-literal/input.js    |  10 ++
 .../pipe-body-with-object-literal/output.js   |  11 ++
 .../pipe-body-with-topic-method-call/exec.js  |   3 +
 .../pipe-body-with-topic-method-call/input.js |   3 +
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 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/exec.js
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 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/options.json
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/options.json
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/exec.js
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 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/options.json
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/options.json
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/input.js
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 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/exec.js
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 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/exec.js
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 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-generator-with-yield/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-generator-with-yield/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-if-else-block/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-if-else-block/output.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/output.js

diff --git a/packages/babel-generator/src/generators/types.ts b/packages/babel-generator/src/generators/types.ts
index b75f5cba5916..779df2d69f8c 100644
--- a/packages/babel-generator/src/generators/types.ts
+++ b/packages/babel-generator/src/generators/types.ts
@@ -238,7 +238,7 @@ export function DecimalLiteral(this: Printer, node: t.DecimalLiteral) {
 }
 
 // Hack pipe operator
-const validTopicTokenSet = new Set(["^", "%", "#"]);
+const validTopicTokenSet = new Set(["^^", "@@", "^", "%", "#"]);
 export function TopicReference(this: Printer) {
   const { topicToken } = this.format;
 
diff --git a/packages/babel-generator/src/index.ts b/packages/babel-generator/src/index.ts
index 104f8325bcc4..6c449e0413bc 100644
--- a/packages/babel-generator/src/index.ts
+++ b/packages/babel-generator/src/index.ts
@@ -203,7 +203,7 @@ export interface GeneratorOptions {
    * For use with the Hack-style pipe operator.
    * Changes what token is used for pipe bodies’ topic references.
    */
-  topicToken?: "^" | "%" | "#";
+  topicToken?: "^^" | "@@" | "^" | "%" | "#";
 }
 
 export interface GeneratorResult {
diff --git a/packages/babel-generator/test/fixtures/types/TopicReference-with-double-at-topicToken/input.js b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-at-topicToken/input.js
new file mode 100644
index 000000000000..e10477e14090
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-at-topicToken/input.js
@@ -0,0 +1 @@
+2 + 3 |> @@.toString(16);
diff --git a/packages/babel-generator/test/fixtures/types/TopicReference-with-double-at-topicToken/options.json b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-at-topicToken/options.json
new file mode 100644
index 000000000000..1267861eb749
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-at-topicToken/options.json
@@ -0,0 +1,4 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]],
+  "topicToken": "@@"
+}
diff --git a/packages/babel-generator/test/fixtures/types/TopicReference-with-double-at-topicToken/output.js b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-at-topicToken/output.js
new file mode 100644
index 000000000000..e10477e14090
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-at-topicToken/output.js
@@ -0,0 +1 @@
+2 + 3 |> @@.toString(16);
diff --git a/packages/babel-generator/test/fixtures/types/TopicReference-with-double-caret-topicToken/input.js b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-caret-topicToken/input.js
new file mode 100644
index 000000000000..b9c814b7922e
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-caret-topicToken/input.js
@@ -0,0 +1 @@
+2 + 3 |> ^^.toString(16);
diff --git a/packages/babel-generator/test/fixtures/types/TopicReference-with-double-caret-topicToken/options.json b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-caret-topicToken/options.json
new file mode 100644
index 000000000000..9d6c1a0bd39b
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-caret-topicToken/options.json
@@ -0,0 +1,4 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]],
+  "topicToken": "^^"
+}
diff --git a/packages/babel-generator/test/fixtures/types/TopicReference-with-double-caret-topicToken/output.js b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-caret-topicToken/output.js
new file mode 100644
index 000000000000..b9c814b7922e
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/types/TopicReference-with-double-caret-topicToken/output.js
@@ -0,0 +1 @@
+2 + 3 |> ^^.toString(16);
diff --git a/packages/babel-generator/test/fixtures/types/TopicReference-with-invalid-topicToken/options.json b/packages/babel-generator/test/fixtures/types/TopicReference-with-invalid-topicToken/options.json
index 3ef07c59571f..069fa9add67e 100644
--- a/packages/babel-generator/test/fixtures/types/TopicReference-with-invalid-topicToken/options.json
+++ b/packages/babel-generator/test/fixtures/types/TopicReference-with-invalid-topicToken/options.json
@@ -1,5 +1,5 @@
 {
   "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "#" }]],
   "topicToken": "invalid",
-  "throws": "The \"topicToken\" generator option must be one of \"^\", \"%\", \"#\" (\"invalid\" received instead)."
+  "throws": "The \"topicToken\" generator option must be one of \"^^\", \"@@\", \"^\", \"%\", \"#\" (\"invalid\" received instead)."
 }
diff --git a/packages/babel-generator/test/fixtures/types/TopicReference-with-missing-topicToken/options.json b/packages/babel-generator/test/fixtures/types/TopicReference-with-missing-topicToken/options.json
index 1911353dc052..abf0f725f667 100644
--- a/packages/babel-generator/test/fixtures/types/TopicReference-with-missing-topicToken/options.json
+++ b/packages/babel-generator/test/fixtures/types/TopicReference-with-missing-topicToken/options.json
@@ -1,4 +1,4 @@
 {
   "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "#" }]],
-  "throws": "The \"topicToken\" generator option must be one of \"^\", \"%\", \"#\" (undefined received instead)."
+  "throws": "The \"topicToken\" generator option must be one of \"^^\", \"@@\", \"^\", \"%\", \"#\" (undefined received instead)."
 }
diff --git a/packages/babel-parser/src/parser/expression.js b/packages/babel-parser/src/parser/expression.js
index 544388abc781..4a2cec82e646 100644
--- a/packages/babel-parser/src/parser/expression.js
+++ b/packages/babel-parser/src/parser/expression.js
@@ -1197,6 +1197,30 @@ export default class ExpressionParser extends LValParser {
         return this.parseTopicReferenceThenEqualsSign(tt.bitwiseXOR, "^");
       }
 
+      case tt.doubleCaret: {
+        const pipeProposal = this.getPluginOption(
+          "pipelineOperator",
+          "proposal",
+        );
+        const pluginTopicToken = this.getPluginOption(
+          "pipelineOperator",
+          "topicToken",
+        );
+
+        // The `^^` token is valid only when:
+        // the pipe-operator proposal is active,
+        // its "pipeProposal" is configured as "hack",
+        // and "topicToken" is configured as "^^".
+        // If the pipe-operator proposal settles on a token that is not ^^,
+        // then this token type may be removed.
+        if (pipeProposal === "hack" && pluginTopicToken === "^^") {
+          return this.parseTopicReference(pipeProposal);
+        } else {
+          throw this.unexpected();
+        }
+      }
+
+      case tt.doubleAt:
       case tt.bitwiseXOR:
       case tt.modulo:
       case tt.hash: {
@@ -1299,10 +1323,10 @@ export default class ExpressionParser extends LValParser {
   // that is followed by an equals sign.
   // See <https://github.com/js-choi/proposal-hack-pipes>.
   // If we find ^= or %= in an expression position
-  // (i.e., the tt.moduloAssign or tt.xorAssign token types),
-  // and if the Hack-pipes proposal is active with ^ or % as its topicToken,
-  // then the ^ or % could be the topic token (e.g., in x |> ^==y or x |> ^===y),
-  // and so we reparse the current token as ^ or %.
+  // (i.e., the tt.moduloAssign or tt.xorAssign token types), and if the
+  // Hack-pipes proposal is active with ^ or % as its topicToken, then the ^ or
+  // % could be the topic token (e.g., in x |> ^==y or x |> ^===y), and so we
+  // reparse the current token as ^ or %.
   // Otherwise, this throws an unexpected-token error.
   parseTopicReferenceThenEqualsSign(
     topicTokenType: TokenType,
@@ -1317,8 +1341,8 @@ export default class ExpressionParser extends LValParser {
       // will consume that “topic token”.
       this.state.type = topicTokenType;
       this.state.value = topicTokenValue;
-      // Rewind the tokenizer to the end of the “topic token”,
-      // so that the following token starts at the equals sign after that topic token.
+      // Rewind the tokenizer to the end of the “topic token”, so that the
+      // following token starts at the equals sign after that topic token.
       this.state.pos--;
       this.state.end--;
       this.state.endLoc.column--;
diff --git a/packages/babel-parser/src/plugin-utils.js b/packages/babel-parser/src/plugin-utils.js
index cb750f16e0ab..d0ed132b7b5e 100644
--- a/packages/babel-parser/src/plugin-utils.js
+++ b/packages/babel-parser/src/plugin-utils.js
@@ -67,7 +67,7 @@ export function getPluginOption(
 }
 
 const PIPELINE_PROPOSALS = ["minimal", "fsharp", "hack", "smart"];
-const TOPIC_TOKENS = ["^", "%", "#"];
+const TOPIC_TOKENS = ["^^", "@@", "^", "%", "#"];
 const RECORD_AND_TUPLE_SYNTAX_TYPES = ["hash", "bar"];
 
 export function validatePlugins(plugins: PluginList) {
diff --git a/packages/babel-parser/src/tokenizer/index.js b/packages/babel-parser/src/tokenizer/index.js
index 9c70fe7ab5ea..9b88e8b3d6b9 100644
--- a/packages/babel-parser/src/tokenizer/index.js
+++ b/packages/babel-parser/src/tokenizer/index.js
@@ -700,6 +700,10 @@ export default class Tokenizer extends ParserErrors {
 
   readToken_caret(): void {
     const next = this.input.charCodeAt(this.state.pos + 1);
+    const pipeProposal = this.getPluginOption("pipelineOperator", "proposal");
+    const topicToken = this.getPluginOption("pipelineOperator", "topicToken");
+    const hackPipeWithDoubleCaretIsActive =
+      pipeProposal === "hack" && topicToken === "^^";
 
     // '^='
     if (next === charCodes.equalsTo && !this.state.inType) {
@@ -708,12 +712,43 @@ export default class Tokenizer extends ParserErrors {
       // it can be merged with tt.assign.
       this.finishOp(tt.xorAssign, 2);
     }
+    // '^^'
+    else if (hackPipeWithDoubleCaretIsActive && next === charCodes.caret) {
+      // `tt.doubleCaret` is only needed to support ^^
+      // as a Hack-pipe topic token.
+      // If the proposal ends up choosing a different token,
+      // it may be removed.
+      this.finishOp(tt.doubleCaret, 2);
+
+      // `^^^` is forbidden and must be separated by a space.
+      const lookaheadCh = this.input.codePointAt(this.state.pos);
+      if (lookaheadCh === charCodes.caret) {
+        throw this.unexpected();
+      }
+    }
     // '^'
     else {
       this.finishOp(tt.bitwiseXOR, 1);
     }
   }
 
+  readToken_atSign(): void {
+    const next = this.input.charCodeAt(this.state.pos + 1);
+
+    // '@@'
+    if (next === charCodes.atSign) {
+      // `tt.doubleAt` is only needed to support @@
+      // as a Hack-pipe topic token.
+      // If the proposal ends up choosing a different token,
+      // it may be removed.
+      this.finishOp(tt.doubleAt, 2);
+    }
+    // '@'
+    else {
+      this.finishOp(tt.at, 1);
+    }
+  }
+
   readToken_plus_min(code: number): void {
     // '+-'
     const next = this.input.charCodeAt(this.state.pos + 1);
@@ -1003,8 +1038,7 @@ export default class Tokenizer extends ParserErrors {
         return;
 
       case charCodes.atSign:
-        ++this.state.pos;
-        this.finishToken(tt.at);
+        this.readToken_atSign();
         return;
 
       case charCodes.numberSign:
diff --git a/packages/babel-parser/src/tokenizer/types.js b/packages/babel-parser/src/tokenizer/types.js
index 7e3744f0da87..a3eef5e8ff0c 100644
--- a/packages/babel-parser/src/tokenizer/types.js
+++ b/packages/babel-parser/src/tokenizer/types.js
@@ -186,8 +186,9 @@ export const tt: { [name: string]: TokenType } = {
   eq: createToken("=", { beforeExpr, isAssign }),
   assign: createToken("_=", { beforeExpr, isAssign }),
   slashAssign: createToken("_=", { beforeExpr, isAssign }),
-  // These are only needed to support % and ^ as a Hack-pipe topic token. When the
-  // proposal settles on a token, the others can be merged with tt.assign.
+  // These are only needed to support % and ^ as a Hack-pipe topic token.
+  // When the proposal settles on a token, the others can be merged with
+  // tt.assign.
   xorAssign: createToken("_=", { beforeExpr, isAssign }),
   moduloAssign: createToken("_=", { beforeExpr, isAssign }),
   // end: isAssign
@@ -195,6 +196,12 @@ export const tt: { [name: string]: TokenType } = {
   incDec: createToken("++/--", { prefix, postfix, startsExpr }),
   bang: createToken("!", { beforeExpr, prefix, startsExpr }),
   tilde: createToken("~", { beforeExpr, prefix, startsExpr }),
+
+  // More possible topic tokens.
+  // When the proposal settles on a token, at least one of these may be removed.
+  doubleCaret: createToken("^^", { startsExpr }),
+  doubleAt: createToken("@@", { startsExpr }),
+
   // start: isBinop
   pipeline: createBinop("|>", 0),
   nullishCoalescing: createBinop("??", 1),
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-first/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-first/input.js
new file mode 100644
index 000000000000..143f5bf23ad0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-first/input.js
@@ -0,0 +1 @@
+value |> @@ + 1
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-first/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-first/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-first/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-first/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-first/output.json
new file mode 100644
index 000000000000..14a12f4fc9ad
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-first/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "+",
+            "right": {
+              "type": "NumericLiteral",
+              "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-last/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-last/input.js
new file mode 100644
index 000000000000..255733f7dae0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-last/input.js
@@ -0,0 +1 @@
+value |> 1 + @@
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-last/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-last/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-last/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-last/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-last/output.json
new file mode 100644
index 000000000000..64f362be927d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-with-topic-last/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "NumericLiteral",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            },
+            "operator": "+",
+            "right": {
+              "type": "TopicReference",
+              "start":13,"end":15,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":15}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-without-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-without-topic/input.js
new file mode 100644
index 000000000000..e952adac15fd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-without-topic/input.js
@@ -0,0 +1 @@
+value |> a + b
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-without-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-without-topic/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-without-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-without-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-without-topic/output.json
new file mode 100644
index 000000000000..6565ae6d9aa2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-addition-without-topic/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":14,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":14}},
+            "left": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"a"},
+              "name": "a"
+            },
+            "operator": "+",
+            "right": {
+              "type": "Identifier",
+              "start":13,"end":14,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":14},"identifierName":"b"},
+              "name": "b"
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-parenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-parenthesized/input.js
new file mode 100644
index 000000000000..bf1d61a76354
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-parenthesized/input.js
@@ -0,0 +1 @@
+value |> (() => @@ + 1)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-parenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-parenthesized/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-parenthesized/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-parenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-parenthesized/output.json
new file mode 100644
index 000000000000..5e034e6dee57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-parenthesized/output.json
@@ -0,0 +1,57 @@
+{
+  "type": "File",
+  "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":10,"end":22,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":22}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BinaryExpression",
+              "start":16,"end":22,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":22}},
+              "left": {
+                "type": "TopicReference",
+                "start":16,"end":18,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":18}}
+              },
+              "operator": "+",
+              "right": {
+                "type": "NumericLiteral",
+                "start":21,"end":22,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":22}},
+                "extra": {
+                  "rawValue": 1,
+                  "raw": "1"
+                },
+                "value": 1
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-unparenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-unparenthesized/input.js
new file mode 100644
index 000000000000..8f18e5449393
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-unparenthesized/input.js
@@ -0,0 +1 @@
+10 |> x => x + @@;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-unparenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-unparenthesized/options.json
new file mode 100644
index 000000000000..0dfb1fc3aa49
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-unparenthesized/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "@@"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-unparenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-unparenthesized/output.json
new file mode 100644
index 000000000000..8266a4927101
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-arrow-function-unparenthesized/output.json
@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized arrow function expression; please wrap it in parentheses. (1:6)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":2,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":2}},
+            "extra": {
+              "rawValue": 10,
+              "raw": "10"
+            },
+            "value": 10
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":6,"end":17,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":17}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"x"},
+                "name": "x"
+              }
+            ],
+            "body": {
+              "type": "BinaryExpression",
+              "start":11,"end":17,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":17}},
+              "left": {
+                "type": "Identifier",
+                "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"x"},
+                "name": "x"
+              },
+              "operator": "+",
+              "right": {
+                "type": "TopicReference",
+                "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17}}
+              }
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-logical-and/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-logical-and/input.js
new file mode 100644
index 000000000000..0c03eacb50de
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-logical-and/input.js
@@ -0,0 +1 @@
+value |> x &&= @@
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-logical-and/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-logical-and/options.json
new file mode 100644
index 000000000000..0dfb1fc3aa49
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-logical-and/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "@@"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-logical-and/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-logical-and/output.json
new file mode 100644
index 000000000000..e3d61d042cdb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-logical-and/output.json
@@ -0,0 +1,44 @@
+{
+  "type": "File",
+  "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized assignment expression; please wrap it in parentheses. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":9,"end":17,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":17}},
+            "operator": "&&=",
+            "left": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"x"},
+              "name": "x"
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-normal/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-normal/input.js
new file mode 100644
index 000000000000..5efad39dbdb4
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-normal/input.js
@@ -0,0 +1 @@
+value |> [x, y] = @@
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-normal/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-normal/options.json
new file mode 100644
index 000000000000..0dfb1fc3aa49
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-normal/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "@@"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-normal/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-normal/output.json
new file mode 100644
index 000000000000..4e13d17f8b5e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-normal/output.json
@@ -0,0 +1,55 @@
+{
+  "type": "File",
+  "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized assignment expression; please wrap it in parentheses. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":9,"end":20,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":20}},
+            "operator": "=",
+            "left": {
+              "type": "ArrayPattern",
+              "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+              "elements": [
+                {
+                  "type": "Identifier",
+                  "start":10,"end":11,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":11},"identifierName":"x"},
+                  "name": "x"
+                },
+                {
+                  "type": "Identifier",
+                  "start":13,"end":14,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":14},"identifierName":"y"},
+                  "name": "y"
+                }
+              ]
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":18,"end":20,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":20}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-plus/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-plus/input.js
new file mode 100644
index 000000000000..ec0dae0a8b87
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-plus/input.js
@@ -0,0 +1 @@
+value |> x += @@
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-plus/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-plus/options.json
new file mode 100644
index 000000000000..0dfb1fc3aa49
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-plus/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "@@"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-plus/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-plus/output.json
new file mode 100644
index 000000000000..8f65e60606a5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-plus/output.json
@@ -0,0 +1,44 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized assignment expression; please wrap it in parentheses. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":9,"end":16,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":16}},
+            "operator": "+=",
+            "left": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"x"},
+              "name": "x"
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":14,"end":16,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":16}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-to-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-to-topic/input.js
new file mode 100644
index 000000000000..7e85477fac1b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-to-topic/input.js
@@ -0,0 +1 @@
+value |> (@@ = 1);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-to-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-to-topic/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-to-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-to-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-to-topic/output.json
new file mode 100644
index 000000000000..1c0352cc28cb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-assignment-to-topic/output.json
@@ -0,0 +1,52 @@
+{
+  "type": "File",
+  "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+  "errors": [
+    "SyntaxError: Invalid left-hand side in assignment expression. (1:10)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":10,"end":16,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":16}},
+            "operator": "=",
+            "left": {
+              "type": "TopicReference",
+              "start":10,"end":12,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":12}}
+            },
+            "right": {
+              "type": "NumericLiteral",
+              "start":15,"end":16,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":16}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-associativity/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-associativity/input.js
new file mode 100644
index 000000000000..c9d398284676
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-associativity/input.js
@@ -0,0 +1 @@
+1 |> f(@@) |> g(@@);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-associativity/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-associativity/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-associativity/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-associativity/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-associativity/output.json
new file mode 100644
index 000000000000..db7ebf40c8f2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-associativity/output.json
@@ -0,0 +1,66 @@
+{
+  "type": "File",
+  "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1}},
+            "extra": {
+              "rawValue": 1,
+              "raw": "1"
+            },
+            "value": 1
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":5,"end":19,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":19}},
+            "left": {
+              "type": "CallExpression",
+              "start":5,"end":10,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":10}},
+              "callee": {
+                "type": "Identifier",
+                "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"f"},
+                "name": "f"
+              },
+              "arguments": [
+                {
+                  "type": "TopicReference",
+                  "start":7,"end":9,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":9}}
+                }
+              ]
+            },
+            "operator": "|>",
+            "right": {
+              "type": "CallExpression",
+              "start":14,"end":19,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":19}},
+              "callee": {
+                "type": "Identifier",
+                "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15},"identifierName":"g"},
+                "name": "g"
+              },
+              "arguments": [
+                {
+                  "type": "TopicReference",
+                  "start":16,"end":18,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":18}}
+                }
+              ]
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-async-await/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-async-await/input.js
new file mode 100644
index 000000000000..f1cfcb23ca41
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-async-await/input.js
@@ -0,0 +1,3 @@
+async function f () {
+  return x |> await @@;
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-async-await/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-async-await/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-async-await/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-async-await/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-async-await/output.json
new file mode 100644
index 000000000000..9c6d1e74bd5b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-async-await/output.json
@@ -0,0 +1,54 @@
+{
+  "type": "File",
+  "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":16,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":16},"identifierName":"f"},
+          "name": "f"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":20,"end":47,"loc":{"start":{"line":1,"column":20},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ReturnStatement",
+              "start":24,"end":45,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":23}},
+              "argument": {
+                "type": "BinaryExpression",
+                "start":31,"end":44,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":22}},
+                "left": {
+                  "type": "Identifier",
+                  "start":31,"end":32,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":10},"identifierName":"x"},
+                  "name": "x"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "AwaitExpression",
+                  "start":36,"end":44,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":22}},
+                  "argument": {
+                    "type": "TopicReference",
+                    "start":42,"end":44,"loc":{"start":{"line":2,"column":20},"end":{"line":2,"column":22}}
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-bare-identifier/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-bare-identifier/input.js
new file mode 100644
index 000000000000..ee911e0ac476
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-bare-identifier/input.js
@@ -0,0 +1 @@
+value |> @foo class { constructor () { @@; } }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-bare-identifier/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-bare-identifier/options.json
new file mode 100644
index 000000000000..d892ab069acf
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-bare-identifier/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    ["decorators", { "decoratorsBeforeExport": false }]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-bare-identifier/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-bare-identifier/output.json
new file mode 100644
index 000000000000..65e2053d6f2a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-bare-identifier/output.json
@@ -0,0 +1,81 @@
+{
+  "type": "File",
+  "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":9,"end":46,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":46}},
+            "decorators": [
+              {
+                "type": "Decorator",
+                "start":9,"end":13,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":13}},
+                "expression": {
+                  "type": "Identifier",
+                  "start":10,"end":13,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":13},"identifierName":"foo"},
+                  "name": "foo"
+                }
+              }
+            ],
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":20,"end":46,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":46}},
+              "body": [
+                {
+                  "type": "ClassMethod",
+                  "start":22,"end":44,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":44}},
+                  "static": false,
+                  "key": {
+                    "type": "Identifier",
+                    "start":22,"end":33,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":33},"identifierName":"constructor"},
+                    "name": "constructor"
+                  },
+                  "computed": false,
+                  "kind": "constructor",
+                  "id": null,
+                  "generator": false,
+                  "async": false,
+                  "params": [],
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":44,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":44}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":39,"end":42,"loc":{"start":{"line":1,"column":39},"end":{"line":1,"column":42}},
+                        "expression": {
+                          "type": "TopicReference",
+                          "start":39,"end":41,"loc":{"start":{"line":1,"column":39},"end":{"line":1,"column":41}}
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-identifier/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-identifier/input.js
new file mode 100644
index 000000000000..e6f627af7cab
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-identifier/input.js
@@ -0,0 +1 @@
+value |> @(foo) class { constructor () { @@; } }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-identifier/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-identifier/options.json
new file mode 100644
index 000000000000..d892ab069acf
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-identifier/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    ["decorators", { "decoratorsBeforeExport": false }]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-identifier/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-identifier/output.json
new file mode 100644
index 000000000000..06455b0c8955
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-identifier/output.json
@@ -0,0 +1,81 @@
+{
+  "type": "File",
+  "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":48}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":48}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":48}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":48}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":9,"end":48,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":48}},
+            "decorators": [
+              {
+                "type": "Decorator",
+                "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+                "expression": {
+                  "type": "Identifier",
+                  "start":11,"end":14,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":14},"identifierName":"foo"},
+                  "name": "foo"
+                }
+              }
+            ],
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":22,"end":48,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":48}},
+              "body": [
+                {
+                  "type": "ClassMethod",
+                  "start":24,"end":46,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":46}},
+                  "static": false,
+                  "key": {
+                    "type": "Identifier",
+                    "start":24,"end":35,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":35},"identifierName":"constructor"},
+                    "name": "constructor"
+                  },
+                  "computed": false,
+                  "kind": "constructor",
+                  "id": null,
+                  "generator": false,
+                  "async": false,
+                  "params": [],
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":39,"end":46,"loc":{"start":{"line":1,"column":39},"end":{"line":1,"column":46}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":41,"end":44,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":44}},
+                        "expression": {
+                          "type": "TopicReference",
+                          "start":41,"end":43,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":43}}
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-topic/input.js
new file mode 100644
index 000000000000..36fed21b87fa
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-topic/input.js
@@ -0,0 +1 @@
+value |> @(@@) class {}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-topic/options.json
new file mode 100644
index 000000000000..d892ab069acf
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-topic/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    ["decorators", { "decoratorsBeforeExport": false }]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-topic/output.json
new file mode 100644
index 000000000000..66492e7e5519
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-decorator-with-parenthesized-topic/output.json
@@ -0,0 +1,48 @@
+{
+  "type": "File",
+  "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":9,"end":23,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":23}},
+            "decorators": [
+              {
+                "type": "Decorator",
+                "start":9,"end":14,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":14}},
+                "expression": {
+                  "type": "TopicReference",
+                  "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+                }
+              }
+            ],
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":21,"end":23,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":23}},
+              "body": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-with-private-property/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-with-private-property/input.js
new file mode 100644
index 000000000000..8e532f6ad703
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-with-private-property/input.js
@@ -0,0 +1,7 @@
+value |> new (class Thing {
+  #property;
+
+  method () {
+    return @@ + this.#property;
+  }
+});
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-with-private-property/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-with-private-property/options.json
new file mode 100644
index 000000000000..fcd51fb78f2c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-with-private-property/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    "classPrivateProperties",
+    "classPrivateMethods"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-with-private-property/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-with-private-property/output.json
new file mode 100644
index 000000000000..5e32fe170d3e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-with-private-property/output.json
@@ -0,0 +1,121 @@
+{
+  "type": "File",
+  "start":0,"end":95,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":3}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":95,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":3}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":95,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":3}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":94,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":2}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "NewExpression",
+            "start":9,"end":94,"loc":{"start":{"line":1,"column":9},"end":{"line":7,"column":2}},
+            "callee": {
+              "type": "ClassExpression",
+              "start":14,"end":93,"loc":{"start":{"line":1,"column":14},"end":{"line":7,"column":1}},
+              "id": {
+                "type": "Identifier",
+                "start":20,"end":25,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":25},"identifierName":"Thing"},
+                "name": "Thing"
+              },
+              "superClass": null,
+              "body": {
+                "type": "ClassBody",
+                "start":26,"end":93,"loc":{"start":{"line":1,"column":26},"end":{"line":7,"column":1}},
+                "body": [
+                  {
+                    "type": "ClassPrivateProperty",
+                    "start":30,"end":40,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":12}},
+                    "static": false,
+                    "key": {
+                      "type": "PrivateName",
+                      "start":30,"end":39,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":11}},
+                      "id": {
+                        "type": "Identifier",
+                        "start":31,"end":39,"loc":{"start":{"line":2,"column":3},"end":{"line":2,"column":11},"identifierName":"property"},
+                        "name": "property"
+                      }
+                    },
+                    "value": null
+                  },
+                  {
+                    "type": "ClassMethod",
+                    "start":44,"end":91,"loc":{"start":{"line":4,"column":2},"end":{"line":6,"column":3}},
+                    "static": false,
+                    "key": {
+                      "type": "Identifier",
+                      "start":44,"end":50,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":8},"identifierName":"method"},
+                      "name": "method"
+                    },
+                    "computed": false,
+                    "kind": "method",
+                    "id": null,
+                    "generator": false,
+                    "async": false,
+                    "params": [],
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":54,"end":91,"loc":{"start":{"line":4,"column":12},"end":{"line":6,"column":3}},
+                      "body": [
+                        {
+                          "type": "ReturnStatement",
+                          "start":60,"end":87,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":31}},
+                          "argument": {
+                            "type": "BinaryExpression",
+                            "start":67,"end":86,"loc":{"start":{"line":5,"column":11},"end":{"line":5,"column":30}},
+                            "left": {
+                              "type": "TopicReference",
+                              "start":67,"end":69,"loc":{"start":{"line":5,"column":11},"end":{"line":5,"column":13}}
+                            },
+                            "operator": "+",
+                            "right": {
+                              "type": "MemberExpression",
+                              "start":72,"end":86,"loc":{"start":{"line":5,"column":16},"end":{"line":5,"column":30}},
+                              "object": {
+                                "type": "ThisExpression",
+                                "start":72,"end":76,"loc":{"start":{"line":5,"column":16},"end":{"line":5,"column":20}}
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "PrivateName",
+                                "start":77,"end":86,"loc":{"start":{"line":5,"column":21},"end":{"line":5,"column":30}},
+                                "id": {
+                                  "type": "Identifier",
+                                  "start":78,"end":86,"loc":{"start":{"line":5,"column":22},"end":{"line":5,"column":30},"identifierName":"property"},
+                                  "name": "property"
+                                }
+                              }
+                            }
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  }
+                ]
+              },
+              "extra": {
+                "parenthesized": true,
+                "parenStart": 13
+              }
+            },
+            "arguments": []
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-without-private-property/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-without-private-property/input.js
new file mode 100644
index 000000000000..6ced0ac19af9
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-without-private-property/input.js
@@ -0,0 +1 @@
+x |> class { constructor () { this.x = @@; } }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-without-private-property/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-without-private-property/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-without-private-property/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-without-private-property/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-without-private-property/output.json
new file mode 100644
index 000000000000..6673187ad7a5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-class-expression-without-private-property/output.json
@@ -0,0 +1,89 @@
+{
+  "type": "File",
+  "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":5,"end":46,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":46}},
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":11,"end":46,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":46}},
+              "body": [
+                {
+                  "type": "ClassMethod",
+                  "start":13,"end":44,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":44}},
+                  "static": false,
+                  "key": {
+                    "type": "Identifier",
+                    "start":13,"end":24,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":24},"identifierName":"constructor"},
+                    "name": "constructor"
+                  },
+                  "computed": false,
+                  "kind": "constructor",
+                  "id": null,
+                  "generator": false,
+                  "async": false,
+                  "params": [],
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":28,"end":44,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":44}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":30,"end":42,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":42}},
+                        "expression": {
+                          "type": "AssignmentExpression",
+                          "start":30,"end":41,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":41}},
+                          "operator": "=",
+                          "left": {
+                            "type": "MemberExpression",
+                            "start":30,"end":36,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":36}},
+                            "object": {
+                              "type": "ThisExpression",
+                              "start":30,"end":34,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":34}}
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":35,"end":36,"loc":{"start":{"line":1,"column":35},"end":{"line":1,"column":36},"identifierName":"x"},
+                              "name": "x"
+                            }
+                          },
+                          "right": {
+                            "type": "TopicReference",
+                            "start":39,"end":41,"loc":{"start":{"line":1,"column":39},"end":{"line":1,"column":41}}
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-comma-topic-pair/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-comma-topic-pair/input.js
new file mode 100644
index 000000000000..f61fb6eaa1ee
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-comma-topic-pair/input.js
@@ -0,0 +1 @@
+10 |> (@@, @@);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-comma-topic-pair/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-comma-topic-pair/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-comma-topic-pair/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-comma-topic-pair/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-comma-topic-pair/output.json
new file mode 100644
index 000000000000..07c3718a305e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-comma-topic-pair/output.json
@@ -0,0 +1,49 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":2,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":2}},
+            "extra": {
+              "rawValue": 10,
+              "raw": "10"
+            },
+            "value": 10
+          },
+          "operator": "|>",
+          "right": {
+            "type": "SequenceExpression",
+            "start":7,"end":13,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":13}},
+            "expressions": [
+              {
+                "type": "TopicReference",
+                "start":7,"end":9,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":9}}
+              },
+              {
+                "type": "TopicReference",
+                "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+              }
+            ],
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 6
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-computed-no-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-computed-no-topic/input.js
new file mode 100644
index 000000000000..5a02dee8ec60
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-computed-no-topic/input.js
@@ -0,0 +1 @@
+value |> a[b]
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-computed-no-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-computed-no-topic/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-computed-no-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-computed-no-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-computed-no-topic/output.json
new file mode 100644
index 000000000000..3959a09863b0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-computed-no-topic/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "MemberExpression",
+            "start":9,"end":13,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":13}},
+            "object": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"a"},
+              "name": "a"
+            },
+            "computed": true,
+            "property": {
+              "type": "Identifier",
+              "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"b"},
+              "name": "b"
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-division/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-division/input.js
new file mode 100644
index 000000000000..0eebef652fe8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-division/input.js
@@ -0,0 +1 @@
+value |> @@ / 2
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-division/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-division/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-division/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-division/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-division/output.json
new file mode 100644
index 000000000000..b270f10daff6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-division/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "/",
+            "right": {
+              "type": "NumericLiteral",
+              "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15}},
+              "extra": {
+                "rawValue": 2,
+                "raw": "2"
+              },
+              "value": 2
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..58a6489b2dea
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { do x += @@; while (x < 50); }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..941f2f506218
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,80 @@
+{
+  "type": "File",
+  "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":43,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":43}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":43,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":43}},
+              "body": [
+                {
+                  "type": "DoWhileStatement",
+                  "start":14,"end":41,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":41}},
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":17,"end":25,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":25}},
+                    "expression": {
+                      "type": "AssignmentExpression",
+                      "start":17,"end":24,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":24}},
+                      "operator": "+=",
+                      "left": {
+                        "type": "Identifier",
+                        "start":17,"end":18,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":18},"identifierName":"x"},
+                        "name": "x"
+                      },
+                      "right": {
+                        "type": "TopicReference",
+                        "start":22,"end":24,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":24}}
+                      }
+                    }
+                  },
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":33,"end":39,"loc":{"start":{"line":1,"column":33},"end":{"line":1,"column":39}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":33,"end":34,"loc":{"start":{"line":1,"column":33},"end":{"line":1,"column":34},"identifierName":"x"},
+                      "name": "x"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "NumericLiteral",
+                      "start":37,"end":39,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":39}},
+                      "extra": {
+                        "rawValue": 50,
+                        "raw": "50"
+                      },
+                      "value": 50
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..b4d49738bd03
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { do x += 1; while (x < @@); }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..19a23bc8d0a9
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-do-while-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,80 @@
+{
+  "type": "File",
+  "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":42}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":42}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":42}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":42}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":42,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":42}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":42,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":42}},
+              "body": [
+                {
+                  "type": "DoWhileStatement",
+                  "start":14,"end":40,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":40}},
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":17,"end":24,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":24}},
+                    "expression": {
+                      "type": "AssignmentExpression",
+                      "start":17,"end":23,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":23}},
+                      "operator": "+=",
+                      "left": {
+                        "type": "Identifier",
+                        "start":17,"end":18,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":18},"identifierName":"x"},
+                        "name": "x"
+                      },
+                      "right": {
+                        "type": "NumericLiteral",
+                        "start":22,"end":23,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":23}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    }
+                  },
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":32,"end":38,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":38}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":32,"end":33,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":33},"identifierName":"x"},
+                      "name": "x"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "TopicReference",
+                      "start":36,"end":38,"loc":{"start":{"line":1,"column":36},"end":{"line":1,"column":38}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..cb61fa5f2fda
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1,3 @@
+async function af () {
+  value |> do { for await (const e of sequence) @@; }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..e1698d7235fb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    "doExpressions"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..fddba25fc5fe
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,93 @@
+{
+  "type": "File",
+  "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17},"identifierName":"af"},
+          "name": "af"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":21,"end":78,"loc":{"start":{"line":1,"column":21},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":25,"end":76,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":53}},
+              "expression": {
+                "type": "BinaryExpression",
+                "start":25,"end":76,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":53}},
+                "left": {
+                  "type": "Identifier",
+                  "start":25,"end":30,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":7},"identifierName":"value"},
+                  "name": "value"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "DoExpression",
+                  "start":34,"end":76,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":53}},
+                  "async": false,
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":76,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":53}},
+                    "body": [
+                      {
+                        "type": "ForOfStatement",
+                        "start":39,"end":74,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":51}},
+                        "await": true,
+                        "left": {
+                          "type": "VariableDeclaration",
+                          "start":50,"end":57,"loc":{"start":{"line":2,"column":27},"end":{"line":2,"column":34}},
+                          "declarations": [
+                            {
+                              "type": "VariableDeclarator",
+                              "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34}},
+                              "id": {
+                                "type": "Identifier",
+                                "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"e"},
+                                "name": "e"
+                              },
+                              "init": null
+                            }
+                          ],
+                          "kind": "const"
+                        },
+                        "right": {
+                          "type": "Identifier",
+                          "start":61,"end":69,"loc":{"start":{"line":2,"column":38},"end":{"line":2,"column":46},"identifierName":"sequence"},
+                          "name": "sequence"
+                        },
+                        "body": {
+                          "type": "ExpressionStatement",
+                          "start":71,"end":74,"loc":{"start":{"line":2,"column":48},"end":{"line":2,"column":51}},
+                          "expression": {
+                            "type": "TopicReference",
+                            "start":71,"end":73,"loc":{"start":{"line":2,"column":48},"end":{"line":2,"column":50}}
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..ae2800e64668
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1,3 @@
+async function af () {
+  value |> do { for await (const e of @@) e; }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..e1698d7235fb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    "doExpressions"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..4f5624112439
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,93 @@
+{
+  "type": "File",
+  "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17},"identifierName":"af"},
+          "name": "af"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":21,"end":71,"loc":{"start":{"line":1,"column":21},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":25,"end":69,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":46}},
+              "expression": {
+                "type": "BinaryExpression",
+                "start":25,"end":69,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":46}},
+                "left": {
+                  "type": "Identifier",
+                  "start":25,"end":30,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":7},"identifierName":"value"},
+                  "name": "value"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "DoExpression",
+                  "start":34,"end":69,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":46}},
+                  "async": false,
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":69,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":46}},
+                    "body": [
+                      {
+                        "type": "ForOfStatement",
+                        "start":39,"end":67,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":44}},
+                        "await": true,
+                        "left": {
+                          "type": "VariableDeclaration",
+                          "start":50,"end":57,"loc":{"start":{"line":2,"column":27},"end":{"line":2,"column":34}},
+                          "declarations": [
+                            {
+                              "type": "VariableDeclarator",
+                              "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34}},
+                              "id": {
+                                "type": "Identifier",
+                                "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"e"},
+                                "name": "e"
+                              },
+                              "init": null
+                            }
+                          ],
+                          "kind": "const"
+                        },
+                        "right": {
+                          "type": "TopicReference",
+                          "start":61,"end":63,"loc":{"start":{"line":2,"column":38},"end":{"line":2,"column":40}}
+                        },
+                        "body": {
+                          "type": "ExpressionStatement",
+                          "start":65,"end":67,"loc":{"start":{"line":2,"column":42},"end":{"line":2,"column":44}},
+                          "expression": {
+                            "type": "Identifier",
+                            "start":65,"end":66,"loc":{"start":{"line":2,"column":42},"end":{"line":2,"column":43},"identifierName":"e"},
+                            "name": "e"
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..cb61fa5f2fda
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/input.js
@@ -0,0 +1,3 @@
+async function af () {
+  value |> do { for await (const e of sequence) @@; }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..273ca998a1cc
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    "doExpressions",
+    "asyncGenerators"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..fddba25fc5fe
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/output.json
@@ -0,0 +1,93 @@
+{
+  "type": "File",
+  "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17},"identifierName":"af"},
+          "name": "af"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":21,"end":78,"loc":{"start":{"line":1,"column":21},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":25,"end":76,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":53}},
+              "expression": {
+                "type": "BinaryExpression",
+                "start":25,"end":76,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":53}},
+                "left": {
+                  "type": "Identifier",
+                  "start":25,"end":30,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":7},"identifierName":"value"},
+                  "name": "value"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "DoExpression",
+                  "start":34,"end":76,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":53}},
+                  "async": false,
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":76,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":53}},
+                    "body": [
+                      {
+                        "type": "ForOfStatement",
+                        "start":39,"end":74,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":51}},
+                        "await": true,
+                        "left": {
+                          "type": "VariableDeclaration",
+                          "start":50,"end":57,"loc":{"start":{"line":2,"column":27},"end":{"line":2,"column":34}},
+                          "declarations": [
+                            {
+                              "type": "VariableDeclarator",
+                              "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34}},
+                              "id": {
+                                "type": "Identifier",
+                                "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"e"},
+                                "name": "e"
+                              },
+                              "init": null
+                            }
+                          ],
+                          "kind": "const"
+                        },
+                        "right": {
+                          "type": "Identifier",
+                          "start":61,"end":69,"loc":{"start":{"line":2,"column":38},"end":{"line":2,"column":46},"identifierName":"sequence"},
+                          "name": "sequence"
+                        },
+                        "body": {
+                          "type": "ExpressionStatement",
+                          "start":71,"end":74,"loc":{"start":{"line":2,"column":48},"end":{"line":2,"column":51}},
+                          "expression": {
+                            "type": "TopicReference",
+                            "start":71,"end":73,"loc":{"start":{"line":2,"column":48},"end":{"line":2,"column":50}}
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..ae2800e64668
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/input.js
@@ -0,0 +1,3 @@
+async function af () {
+  value |> do { for await (const e of @@) e; }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..273ca998a1cc
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    "doExpressions",
+    "asyncGenerators"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..4f5624112439
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/output.json
@@ -0,0 +1,93 @@
+{
+  "type": "File",
+  "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17},"identifierName":"af"},
+          "name": "af"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":21,"end":71,"loc":{"start":{"line":1,"column":21},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":25,"end":69,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":46}},
+              "expression": {
+                "type": "BinaryExpression",
+                "start":25,"end":69,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":46}},
+                "left": {
+                  "type": "Identifier",
+                  "start":25,"end":30,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":7},"identifierName":"value"},
+                  "name": "value"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "DoExpression",
+                  "start":34,"end":69,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":46}},
+                  "async": false,
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":69,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":46}},
+                    "body": [
+                      {
+                        "type": "ForOfStatement",
+                        "start":39,"end":67,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":44}},
+                        "await": true,
+                        "left": {
+                          "type": "VariableDeclaration",
+                          "start":50,"end":57,"loc":{"start":{"line":2,"column":27},"end":{"line":2,"column":34}},
+                          "declarations": [
+                            {
+                              "type": "VariableDeclarator",
+                              "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34}},
+                              "id": {
+                                "type": "Identifier",
+                                "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"e"},
+                                "name": "e"
+                              },
+                              "init": null
+                            }
+                          ],
+                          "kind": "const"
+                        },
+                        "right": {
+                          "type": "TopicReference",
+                          "start":61,"end":63,"loc":{"start":{"line":2,"column":38},"end":{"line":2,"column":40}}
+                        },
+                        "body": {
+                          "type": "ExpressionStatement",
+                          "start":65,"end":67,"loc":{"start":{"line":2,"column":42},"end":{"line":2,"column":44}},
+                          "expression": {
+                            "type": "Identifier",
+                            "start":65,"end":66,"loc":{"start":{"line":2,"column":42},"end":{"line":2,"column":43},"identifierName":"e"},
+                            "name": "e"
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..c7d1ade86394
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { for (let i = 0; i < n; i += 1) @@; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..de572e961fe4
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,110 @@
+{
+  "type": "File",
+  "start":0,"end":50,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":50}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":50,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":50}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":50,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":50}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":50,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":50}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":50,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":50}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":50,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":50}},
+              "body": [
+                {
+                  "type": "ForStatement",
+                  "start":14,"end":48,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":48}},
+                  "init": {
+                    "type": "VariableDeclaration",
+                    "start":19,"end":28,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":28}},
+                    "declarations": [
+                      {
+                        "type": "VariableDeclarator",
+                        "start":23,"end":28,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":28}},
+                        "id": {
+                          "type": "Identifier",
+                          "start":23,"end":24,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":24},"identifierName":"i"},
+                          "name": "i"
+                        },
+                        "init": {
+                          "type": "NumericLiteral",
+                          "start":27,"end":28,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":28}},
+                          "extra": {
+                            "rawValue": 0,
+                            "raw": "0"
+                          },
+                          "value": 0
+                        }
+                      }
+                    ],
+                    "kind": "let"
+                  },
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":30,"end":35,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":35}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":30,"end":31,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":31},"identifierName":"i"},
+                      "name": "i"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "Identifier",
+                      "start":34,"end":35,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":35},"identifierName":"n"},
+                      "name": "n"
+                    }
+                  },
+                  "update": {
+                    "type": "AssignmentExpression",
+                    "start":37,"end":43,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":43}},
+                    "operator": "+=",
+                    "left": {
+                      "type": "Identifier",
+                      "start":37,"end":38,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":38},"identifierName":"i"},
+                      "name": "i"
+                    },
+                    "right": {
+                      "type": "NumericLiteral",
+                      "start":42,"end":43,"loc":{"start":{"line":1,"column":42},"end":{"line":1,"column":43}},
+                      "extra": {
+                        "rawValue": 1,
+                        "raw": "1"
+                      },
+                      "value": 1
+                    }
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":45,"end":48,"loc":{"start":{"line":1,"column":45},"end":{"line":1,"column":48}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":45,"end":47,"loc":{"start":{"line":1,"column":45},"end":{"line":1,"column":47}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..88ec2db5becb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { for (let i = @@; predicate(i, @@); i += @@) i; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..3afffc17b927
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,106 @@
+{
+  "type": "File",
+  "start":0,"end":62,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":62}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":62,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":62}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":62,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":62}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":62,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":62}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":62,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":62}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":62,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":62}},
+              "body": [
+                {
+                  "type": "ForStatement",
+                  "start":14,"end":60,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":60}},
+                  "init": {
+                    "type": "VariableDeclaration",
+                    "start":19,"end":29,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":29}},
+                    "declarations": [
+                      {
+                        "type": "VariableDeclarator",
+                        "start":23,"end":29,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":29}},
+                        "id": {
+                          "type": "Identifier",
+                          "start":23,"end":24,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":24},"identifierName":"i"},
+                          "name": "i"
+                        },
+                        "init": {
+                          "type": "TopicReference",
+                          "start":27,"end":29,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":29}}
+                        }
+                      }
+                    ],
+                    "kind": "let"
+                  },
+                  "test": {
+                    "type": "CallExpression",
+                    "start":31,"end":47,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":47}},
+                    "callee": {
+                      "type": "Identifier",
+                      "start":31,"end":40,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":40},"identifierName":"predicate"},
+                      "name": "predicate"
+                    },
+                    "arguments": [
+                      {
+                        "type": "Identifier",
+                        "start":41,"end":42,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":42},"identifierName":"i"},
+                        "name": "i"
+                      },
+                      {
+                        "type": "TopicReference",
+                        "start":44,"end":46,"loc":{"start":{"line":1,"column":44},"end":{"line":1,"column":46}}
+                      }
+                    ]
+                  },
+                  "update": {
+                    "type": "AssignmentExpression",
+                    "start":49,"end":56,"loc":{"start":{"line":1,"column":49},"end":{"line":1,"column":56}},
+                    "operator": "+=",
+                    "left": {
+                      "type": "Identifier",
+                      "start":49,"end":50,"loc":{"start":{"line":1,"column":49},"end":{"line":1,"column":50},"identifierName":"i"},
+                      "name": "i"
+                    },
+                    "right": {
+                      "type": "TopicReference",
+                      "start":54,"end":56,"loc":{"start":{"line":1,"column":54},"end":{"line":1,"column":56}}
+                    }
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":58,"end":60,"loc":{"start":{"line":1,"column":58},"end":{"line":1,"column":60}},
+                    "expression": {
+                      "type": "Identifier",
+                      "start":58,"end":59,"loc":{"start":{"line":1,"column":58},"end":{"line":1,"column":59},"identifierName":"i"},
+                      "name": "i"
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..57496ab45d9a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { for (e in object) @@; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..daa667eaaed9
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,61 @@
+{
+  "type": "File",
+  "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":37}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":37}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":37}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":37}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":37,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":37}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":37,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":37}},
+              "body": [
+                {
+                  "type": "ForInStatement",
+                  "start":14,"end":35,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":35}},
+                  "left": {
+                    "type": "Identifier",
+                    "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"e"},
+                    "name": "e"
+                  },
+                  "right": {
+                    "type": "Identifier",
+                    "start":24,"end":30,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":30},"identifierName":"object"},
+                    "name": "object"
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":32,"end":35,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":35}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":32,"end":34,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":34}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..7055705d3c45
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { for (e in @@) e; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..f230de3579f5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-in-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,61 @@
+{
+  "type": "File",
+  "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":32,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":32}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":32,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":32}},
+              "body": [
+                {
+                  "type": "ForInStatement",
+                  "start":14,"end":30,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":30}},
+                  "left": {
+                    "type": "Identifier",
+                    "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"e"},
+                    "name": "e"
+                  },
+                  "right": {
+                    "type": "TopicReference",
+                    "start":24,"end":26,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":26}}
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":28,"end":30,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":30}},
+                    "expression": {
+                      "type": "Identifier",
+                      "start":28,"end":29,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":29},"identifierName":"e"},
+                      "name": "e"
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..38f774b373d0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { for (e of sequence) @@; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..45b65d93e930
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":39,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":39}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":39,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":39}},
+              "body": [
+                {
+                  "type": "ForOfStatement",
+                  "start":14,"end":37,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":37}},
+                  "await": false,
+                  "left": {
+                    "type": "Identifier",
+                    "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"e"},
+                    "name": "e"
+                  },
+                  "right": {
+                    "type": "Identifier",
+                    "start":24,"end":32,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":32},"identifierName":"sequence"},
+                    "name": "sequence"
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":34,"end":37,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":37}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":34,"end":36,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":36}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..3dc83d2f6a96
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { for (e of @@) e; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..0a487cc24354
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-for-of-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":32,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":32}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":32,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":32}},
+              "body": [
+                {
+                  "type": "ForOfStatement",
+                  "start":14,"end":30,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":30}},
+                  "await": false,
+                  "left": {
+                    "type": "Identifier",
+                    "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"e"},
+                    "name": "e"
+                  },
+                  "right": {
+                    "type": "TopicReference",
+                    "start":24,"end":26,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":26}}
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":28,"end":30,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":30}},
+                    "expression": {
+                      "type": "Identifier",
+                      "start":28,"end":29,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":29},"identifierName":"e"},
+                      "name": "e"
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-body/input.js
new file mode 100644
index 000000000000..b0860614c647
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-body/input.js
@@ -0,0 +1 @@
+value |> do { if (yes) null; else if (no) @@; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-body/output.json
new file mode 100644
index 000000000000..be79908de4c8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-body/output.json
@@ -0,0 +1,74 @@
+{
+  "type": "File",
+  "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":47}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":47}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":47}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":47}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":47,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":47}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":47,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":47}},
+              "body": [
+                {
+                  "type": "IfStatement",
+                  "start":14,"end":45,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":45}},
+                  "test": {
+                    "type": "Identifier",
+                    "start":18,"end":21,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":21},"identifierName":"yes"},
+                    "name": "yes"
+                  },
+                  "consequent": {
+                    "type": "ExpressionStatement",
+                    "start":23,"end":28,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":28}},
+                    "expression": {
+                      "type": "NullLiteral",
+                      "start":23,"end":27,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":27}}
+                    }
+                  },
+                  "alternate": {
+                    "type": "IfStatement",
+                    "start":34,"end":45,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":45}},
+                    "test": {
+                      "type": "Identifier",
+                      "start":38,"end":40,"loc":{"start":{"line":1,"column":38},"end":{"line":1,"column":40},"identifierName":"no"},
+                      "name": "no"
+                    },
+                    "consequent": {
+                      "type": "ExpressionStatement",
+                      "start":42,"end":45,"loc":{"start":{"line":1,"column":42},"end":{"line":1,"column":45}},
+                      "expression": {
+                        "type": "TopicReference",
+                        "start":42,"end":44,"loc":{"start":{"line":1,"column":42},"end":{"line":1,"column":44}}
+                      }
+                    },
+                    "alternate": null
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-if-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-if-body/input.js
new file mode 100644
index 000000000000..42b501cfbf76
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-if-body/input.js
@@ -0,0 +1 @@
+value |> do { if (yes) null; else @@; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-if-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-if-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-if-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-if-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-if-body/output.json
new file mode 100644
index 000000000000..dc4340eba991
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-else-if-body/output.json
@@ -0,0 +1,64 @@
+{
+  "type": "File",
+  "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":39,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":39}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":39,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":39}},
+              "body": [
+                {
+                  "type": "IfStatement",
+                  "start":14,"end":37,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":37}},
+                  "test": {
+                    "type": "Identifier",
+                    "start":18,"end":21,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":21},"identifierName":"yes"},
+                    "name": "yes"
+                  },
+                  "consequent": {
+                    "type": "ExpressionStatement",
+                    "start":23,"end":28,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":28}},
+                    "expression": {
+                      "type": "NullLiteral",
+                      "start":23,"end":27,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":27}}
+                    }
+                  },
+                  "alternate": {
+                    "type": "ExpressionStatement",
+                    "start":34,"end":37,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":37}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":34,"end":36,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":36}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-body/input.js
new file mode 100644
index 000000000000..9c74bc58330a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-body/input.js
@@ -0,0 +1 @@
+value |> do { if (yes) @@; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-body/output.json
new file mode 100644
index 000000000000..e16a87fba31f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-body/output.json
@@ -0,0 +1,57 @@
+{
+  "type": "File",
+  "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":28,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":28}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":28,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":28}},
+              "body": [
+                {
+                  "type": "IfStatement",
+                  "start":14,"end":26,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":26}},
+                  "test": {
+                    "type": "Identifier",
+                    "start":18,"end":21,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":21},"identifierName":"yes"},
+                    "name": "yes"
+                  },
+                  "consequent": {
+                    "type": "ExpressionStatement",
+                    "start":23,"end":26,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":26}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":23,"end":25,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":25}}
+                    }
+                  },
+                  "alternate": null
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-head/input.js
new file mode 100644
index 000000000000..892ead81cb88
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-head/input.js
@@ -0,0 +1 @@
+value |> do { if (@@) 1; else 0; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-head/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-head/output.json
new file mode 100644
index 000000000000..727a3813b9f7
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-if-statement-and-topic-in-if-head/output.json
@@ -0,0 +1,73 @@
+{
+  "type": "File",
+  "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":34}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":34}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":34}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":34}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":34,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":34}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":34,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":34}},
+              "body": [
+                {
+                  "type": "IfStatement",
+                  "start":14,"end":32,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":32}},
+                  "test": {
+                    "type": "TopicReference",
+                    "start":18,"end":20,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":20}}
+                  },
+                  "consequent": {
+                    "type": "ExpressionStatement",
+                    "start":22,"end":24,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":24}},
+                    "expression": {
+                      "type": "NumericLiteral",
+                      "start":22,"end":23,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":23}},
+                      "extra": {
+                        "rawValue": 1,
+                        "raw": "1"
+                      },
+                      "value": 1
+                    }
+                  },
+                  "alternate": {
+                    "type": "ExpressionStatement",
+                    "start":30,"end":32,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":32}},
+                    "expression": {
+                      "type": "NumericLiteral",
+                      "start":30,"end":31,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":31}},
+                      "extra": {
+                        "rawValue": 0,
+                        "raw": "0"
+                      },
+                      "value": 0
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-body/input.js
new file mode 100644
index 000000000000..09fdf2209773
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-body/input.js
@@ -0,0 +1,7 @@
+value |> do {
+  switch (number) {
+    case 0: @@;
+    case 1: @@ + 1;
+    default: @@ + 10;
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-body/output.json
new file mode 100644
index 000000000000..3fa9c9962c8b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-body/output.json
@@ -0,0 +1,139 @@
+{
+  "type": "File",
+  "start":0,"end":97,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":97,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":97,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":97,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":97,"loc":{"start":{"line":1,"column":9},"end":{"line":7,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":97,"loc":{"start":{"line":1,"column":12},"end":{"line":7,"column":1}},
+              "body": [
+                {
+                  "type": "SwitchStatement",
+                  "start":16,"end":95,"loc":{"start":{"line":2,"column":2},"end":{"line":6,"column":3}},
+                  "discriminant": {
+                    "type": "Identifier",
+                    "start":24,"end":30,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":16},"identifierName":"number"},
+                    "name": "number"
+                  },
+                  "cases": [
+                    {
+                      "type": "SwitchCase",
+                      "start":38,"end":49,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":15}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":46,"end":49,"loc":{"start":{"line":3,"column":12},"end":{"line":3,"column":15}},
+                          "expression": {
+                            "type": "TopicReference",
+                            "start":46,"end":48,"loc":{"start":{"line":3,"column":12},"end":{"line":3,"column":14}}
+                          }
+                        }
+                      ],
+                      "test": {
+                        "type": "NumericLiteral",
+                        "start":43,"end":44,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":10}},
+                        "extra": {
+                          "rawValue": 0,
+                          "raw": "0"
+                        },
+                        "value": 0
+                      }
+                    },
+                    {
+                      "type": "SwitchCase",
+                      "start":54,"end":69,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":19}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":62,"end":69,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":19}},
+                          "expression": {
+                            "type": "BinaryExpression",
+                            "start":62,"end":68,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":18}},
+                            "left": {
+                              "type": "TopicReference",
+                              "start":62,"end":64,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":14}}
+                            },
+                            "operator": "+",
+                            "right": {
+                              "type": "NumericLiteral",
+                              "start":67,"end":68,"loc":{"start":{"line":4,"column":17},"end":{"line":4,"column":18}},
+                              "extra": {
+                                "rawValue": 1,
+                                "raw": "1"
+                              },
+                              "value": 1
+                            }
+                          }
+                        }
+                      ],
+                      "test": {
+                        "type": "NumericLiteral",
+                        "start":59,"end":60,"loc":{"start":{"line":4,"column":9},"end":{"line":4,"column":10}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    },
+                    {
+                      "type": "SwitchCase",
+                      "start":74,"end":91,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":21}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":83,"end":91,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":21}},
+                          "expression": {
+                            "type": "BinaryExpression",
+                            "start":83,"end":90,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":20}},
+                            "left": {
+                              "type": "TopicReference",
+                              "start":83,"end":85,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":15}}
+                            },
+                            "operator": "+",
+                            "right": {
+                              "type": "NumericLiteral",
+                              "start":88,"end":90,"loc":{"start":{"line":5,"column":18},"end":{"line":5,"column":20}},
+                              "extra": {
+                                "rawValue": 10,
+                                "raw": "10"
+                              },
+                              "value": 10
+                            }
+                          }
+                        }
+                      ],
+                      "test": null
+                    }
+                  ]
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-head/input.js
new file mode 100644
index 000000000000..26325cc8adea
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-head/input.js
@@ -0,0 +1,7 @@
+value |> do {
+  switch (@@) {
+    case 0: 50;
+    case 1: 60;
+    default: 70;
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-head/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-head/output.json
new file mode 100644
index 000000000000..93929e99ee58
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-switch-statement-and-topic-in-switch-head/output.json
@@ -0,0 +1,125 @@
+{
+  "type": "File",
+  "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":84,"loc":{"start":{"line":1,"column":9},"end":{"line":7,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":84,"loc":{"start":{"line":1,"column":12},"end":{"line":7,"column":1}},
+              "body": [
+                {
+                  "type": "SwitchStatement",
+                  "start":16,"end":82,"loc":{"start":{"line":2,"column":2},"end":{"line":6,"column":3}},
+                  "discriminant": {
+                    "type": "TopicReference",
+                    "start":24,"end":26,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":12}}
+                  },
+                  "cases": [
+                    {
+                      "type": "SwitchCase",
+                      "start":34,"end":45,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":15}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":42,"end":45,"loc":{"start":{"line":3,"column":12},"end":{"line":3,"column":15}},
+                          "expression": {
+                            "type": "NumericLiteral",
+                            "start":42,"end":44,"loc":{"start":{"line":3,"column":12},"end":{"line":3,"column":14}},
+                            "extra": {
+                              "rawValue": 50,
+                              "raw": "50"
+                            },
+                            "value": 50
+                          }
+                        }
+                      ],
+                      "test": {
+                        "type": "NumericLiteral",
+                        "start":39,"end":40,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":10}},
+                        "extra": {
+                          "rawValue": 0,
+                          "raw": "0"
+                        },
+                        "value": 0
+                      }
+                    },
+                    {
+                      "type": "SwitchCase",
+                      "start":50,"end":61,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":15}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":58,"end":61,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":15}},
+                          "expression": {
+                            "type": "NumericLiteral",
+                            "start":58,"end":60,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":14}},
+                            "extra": {
+                              "rawValue": 60,
+                              "raw": "60"
+                            },
+                            "value": 60
+                          }
+                        }
+                      ],
+                      "test": {
+                        "type": "NumericLiteral",
+                        "start":55,"end":56,"loc":{"start":{"line":4,"column":9},"end":{"line":4,"column":10}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    },
+                    {
+                      "type": "SwitchCase",
+                      "start":66,"end":78,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":16}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":75,"end":78,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":16}},
+                          "expression": {
+                            "type": "NumericLiteral",
+                            "start":75,"end":77,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":15}},
+                            "extra": {
+                              "rawValue": 70,
+                              "raw": "70"
+                            },
+                            "value": 70
+                          }
+                        }
+                      ],
+                      "test": null
+                    }
+                  ]
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-topic-identity/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-topic-identity/input.js
new file mode 100644
index 000000000000..542c2f139d46
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-topic-identity/input.js
@@ -0,0 +1 @@
+value |> do { @@; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-topic-identity/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-topic-identity/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-topic-identity/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-topic-identity/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-topic-identity/output.json
new file mode 100644
index 000000000000..2c53651ce7fe
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-topic-identity/output.json
@@ -0,0 +1,47 @@
+{
+  "type": "File",
+  "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":19,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":19}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":19,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":19}},
+              "body": [
+                {
+                  "type": "ExpressionStatement",
+                  "start":14,"end":17,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":17}},
+                  "expression": {
+                    "type": "TopicReference",
+                    "start":14,"end":16,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":16}}
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/input.js
new file mode 100644
index 000000000000..670c3a5242a4
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/input.js
@@ -0,0 +1,4 @@
+value |> do {
+  try { JSON.parse(@@); }
+  catch (error) { console.error(@@); }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/output.json
new file mode 100644
index 000000000000..eae50a367908
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/output.json
@@ -0,0 +1,125 @@
+{
+  "type": "File",
+  "start":0,"end":80,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":80,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":80,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":80,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":80,"loc":{"start":{"line":1,"column":9},"end":{"line":4,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":80,"loc":{"start":{"line":1,"column":12},"end":{"line":4,"column":1}},
+              "body": [
+                {
+                  "type": "TryStatement",
+                  "start":16,"end":78,"loc":{"start":{"line":2,"column":2},"end":{"line":3,"column":38}},
+                  "block": {
+                    "type": "BlockStatement",
+                    "start":20,"end":39,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":25}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":22,"end":37,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":23}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":22,"end":36,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":22}},
+                          "callee": {
+                            "type": "MemberExpression",
+                            "start":22,"end":32,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":18}},
+                            "object": {
+                              "type": "Identifier",
+                              "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
+                              "name": "JSON"
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
+                              "name": "parse"
+                            }
+                          },
+                          "arguments": [
+                            {
+                              "type": "TopicReference",
+                              "start":33,"end":35,"loc":{"start":{"line":2,"column":19},"end":{"line":2,"column":21}}
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  },
+                  "handler": {
+                    "type": "CatchClause",
+                    "start":42,"end":78,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":38}},
+                    "param": {
+                      "type": "Identifier",
+                      "start":49,"end":54,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":14},"identifierName":"error"},
+                      "name": "error"
+                    },
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":56,"end":78,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":38}},
+                      "body": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":58,"end":76,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":36}},
+                          "expression": {
+                            "type": "CallExpression",
+                            "start":58,"end":75,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":35}},
+                            "callee": {
+                              "type": "MemberExpression",
+                              "start":58,"end":71,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":31}},
+                              "object": {
+                                "type": "Identifier",
+                                "start":58,"end":65,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
+                                "name": "console"
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "Identifier",
+                                "start":66,"end":71,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            },
+                            "arguments": [
+                              {
+                                "type": "TopicReference",
+                                "start":72,"end":74,"loc":{"start":{"line":3,"column":32},"end":{"line":3,"column":34}}
+                              }
+                            ]
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  },
+                  "finalizer": null
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/input.js
new file mode 100644
index 000000000000..fd1f56af9719
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/input.js
@@ -0,0 +1,5 @@
+value |> do {
+  try { JSON.parse(whatever); }
+  catch (error) { console.error(error); }
+  finally { something(@@); }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/output.json
new file mode 100644
index 000000000000..798e55fdc030
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/output.json
@@ -0,0 +1,152 @@
+{
+  "type": "File",
+  "start":0,"end":118,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":118,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":118,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":118,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":118,"loc":{"start":{"line":1,"column":9},"end":{"line":5,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":118,"loc":{"start":{"line":1,"column":12},"end":{"line":5,"column":1}},
+              "body": [
+                {
+                  "type": "TryStatement",
+                  "start":16,"end":116,"loc":{"start":{"line":2,"column":2},"end":{"line":4,"column":28}},
+                  "block": {
+                    "type": "BlockStatement",
+                    "start":20,"end":45,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":31}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":22,"end":43,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":29}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":22,"end":42,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":28}},
+                          "callee": {
+                            "type": "MemberExpression",
+                            "start":22,"end":32,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":18}},
+                            "object": {
+                              "type": "Identifier",
+                              "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
+                              "name": "JSON"
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
+                              "name": "parse"
+                            }
+                          },
+                          "arguments": [
+                            {
+                              "type": "Identifier",
+                              "start":33,"end":41,"loc":{"start":{"line":2,"column":19},"end":{"line":2,"column":27},"identifierName":"whatever"},
+                              "name": "whatever"
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  },
+                  "handler": {
+                    "type": "CatchClause",
+                    "start":48,"end":87,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":41}},
+                    "param": {
+                      "type": "Identifier",
+                      "start":55,"end":60,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":14},"identifierName":"error"},
+                      "name": "error"
+                    },
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":62,"end":87,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":41}},
+                      "body": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":64,"end":85,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":39}},
+                          "expression": {
+                            "type": "CallExpression",
+                            "start":64,"end":84,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":38}},
+                            "callee": {
+                              "type": "MemberExpression",
+                              "start":64,"end":77,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":31}},
+                              "object": {
+                                "type": "Identifier",
+                                "start":64,"end":71,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
+                                "name": "console"
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "Identifier",
+                                "start":72,"end":77,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            },
+                            "arguments": [
+                              {
+                                "type": "Identifier",
+                                "start":78,"end":83,"loc":{"start":{"line":3,"column":32},"end":{"line":3,"column":37},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            ]
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  },
+                  "finalizer": {
+                    "type": "BlockStatement",
+                    "start":98,"end":116,"loc":{"start":{"line":4,"column":10},"end":{"line":4,"column":28}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":100,"end":114,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":26}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":100,"end":113,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":25}},
+                          "callee": {
+                            "type": "Identifier",
+                            "start":100,"end":109,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":21},"identifierName":"something"},
+                            "name": "something"
+                          },
+                          "arguments": [
+                            {
+                              "type": "TopicReference",
+                              "start":110,"end":112,"loc":{"start":{"line":4,"column":22},"end":{"line":4,"column":24}}
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/input.js
new file mode 100644
index 000000000000..cfc55357ab3e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/input.js
@@ -0,0 +1,5 @@
+value |> do {
+  try { JSON.parse(@@); }
+  catch (error) { console.error(error); }
+  finally { something(); }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/output.json
new file mode 100644
index 000000000000..963ec3e5f04b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/output.json
@@ -0,0 +1,146 @@
+{
+  "type": "File",
+  "start":0,"end":110,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":110,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":110,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":110,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":110,"loc":{"start":{"line":1,"column":9},"end":{"line":5,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":110,"loc":{"start":{"line":1,"column":12},"end":{"line":5,"column":1}},
+              "body": [
+                {
+                  "type": "TryStatement",
+                  "start":16,"end":108,"loc":{"start":{"line":2,"column":2},"end":{"line":4,"column":26}},
+                  "block": {
+                    "type": "BlockStatement",
+                    "start":20,"end":39,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":25}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":22,"end":37,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":23}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":22,"end":36,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":22}},
+                          "callee": {
+                            "type": "MemberExpression",
+                            "start":22,"end":32,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":18}},
+                            "object": {
+                              "type": "Identifier",
+                              "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
+                              "name": "JSON"
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
+                              "name": "parse"
+                            }
+                          },
+                          "arguments": [
+                            {
+                              "type": "TopicReference",
+                              "start":33,"end":35,"loc":{"start":{"line":2,"column":19},"end":{"line":2,"column":21}}
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  },
+                  "handler": {
+                    "type": "CatchClause",
+                    "start":42,"end":81,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":41}},
+                    "param": {
+                      "type": "Identifier",
+                      "start":49,"end":54,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":14},"identifierName":"error"},
+                      "name": "error"
+                    },
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":56,"end":81,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":41}},
+                      "body": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":58,"end":79,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":39}},
+                          "expression": {
+                            "type": "CallExpression",
+                            "start":58,"end":78,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":38}},
+                            "callee": {
+                              "type": "MemberExpression",
+                              "start":58,"end":71,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":31}},
+                              "object": {
+                                "type": "Identifier",
+                                "start":58,"end":65,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
+                                "name": "console"
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "Identifier",
+                                "start":66,"end":71,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            },
+                            "arguments": [
+                              {
+                                "type": "Identifier",
+                                "start":72,"end":77,"loc":{"start":{"line":3,"column":32},"end":{"line":3,"column":37},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            ]
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  },
+                  "finalizer": {
+                    "type": "BlockStatement",
+                    "start":92,"end":108,"loc":{"start":{"line":4,"column":10},"end":{"line":4,"column":26}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":94,"end":106,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":24}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":94,"end":105,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":23}},
+                          "callee": {
+                            "type": "Identifier",
+                            "start":94,"end":103,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":21},"identifierName":"something"},
+                            "name": "something"
+                          },
+                          "arguments": []
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-statements-topic-in-try-clause/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-statements-topic-in-try-clause/input.js
new file mode 100644
index 000000000000..f8b245e1dc45
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-statements-topic-in-try-clause/input.js
@@ -0,0 +1,4 @@
+value |> do {
+  try { JSON.parse(@@); }
+  catch (error) { console.error(error); }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-statements-topic-in-try-clause/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-statements-topic-in-try-clause/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-statements-topic-in-try-clause/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-statements-topic-in-try-clause/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-statements-topic-in-try-clause/output.json
new file mode 100644
index 000000000000..11241eb3ca0e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-try-catch-statements-topic-in-try-clause/output.json
@@ -0,0 +1,126 @@
+{
+  "type": "File",
+  "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":83,"loc":{"start":{"line":1,"column":9},"end":{"line":4,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":83,"loc":{"start":{"line":1,"column":12},"end":{"line":4,"column":1}},
+              "body": [
+                {
+                  "type": "TryStatement",
+                  "start":16,"end":81,"loc":{"start":{"line":2,"column":2},"end":{"line":3,"column":41}},
+                  "block": {
+                    "type": "BlockStatement",
+                    "start":20,"end":39,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":25}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":22,"end":37,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":23}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":22,"end":36,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":22}},
+                          "callee": {
+                            "type": "MemberExpression",
+                            "start":22,"end":32,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":18}},
+                            "object": {
+                              "type": "Identifier",
+                              "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
+                              "name": "JSON"
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
+                              "name": "parse"
+                            }
+                          },
+                          "arguments": [
+                            {
+                              "type": "TopicReference",
+                              "start":33,"end":35,"loc":{"start":{"line":2,"column":19},"end":{"line":2,"column":21}}
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  },
+                  "handler": {
+                    "type": "CatchClause",
+                    "start":42,"end":81,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":41}},
+                    "param": {
+                      "type": "Identifier",
+                      "start":49,"end":54,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":14},"identifierName":"error"},
+                      "name": "error"
+                    },
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":56,"end":81,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":41}},
+                      "body": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":58,"end":79,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":39}},
+                          "expression": {
+                            "type": "CallExpression",
+                            "start":58,"end":78,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":38}},
+                            "callee": {
+                              "type": "MemberExpression",
+                              "start":58,"end":71,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":31}},
+                              "object": {
+                                "type": "Identifier",
+                                "start":58,"end":65,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
+                                "name": "console"
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "Identifier",
+                                "start":66,"end":71,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            },
+                            "arguments": [
+                              {
+                                "type": "Identifier",
+                                "start":72,"end":77,"loc":{"start":{"line":3,"column":32},"end":{"line":3,"column":37},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            ]
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  },
+                  "finalizer": null
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..1b08677c6fed
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { while (x < 50) x += @@; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..ac3f99102fec
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-body/output.json
@@ -0,0 +1,80 @@
+{
+  "type": "File",
+  "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":39,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":39}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":39,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":39}},
+              "body": [
+                {
+                  "type": "WhileStatement",
+                  "start":14,"end":37,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":37}},
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":21,"end":27,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":27}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":21,"end":22,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":22},"identifierName":"x"},
+                      "name": "x"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "NumericLiteral",
+                      "start":25,"end":27,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":27}},
+                      "extra": {
+                        "rawValue": 50,
+                        "raw": "50"
+                      },
+                      "value": 50
+                    }
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":29,"end":37,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":37}},
+                    "expression": {
+                      "type": "AssignmentExpression",
+                      "start":29,"end":36,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":36}},
+                      "operator": "+=",
+                      "left": {
+                        "type": "Identifier",
+                        "start":29,"end":30,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":30},"identifierName":"x"},
+                        "name": "x"
+                      },
+                      "right": {
+                        "type": "TopicReference",
+                        "start":34,"end":36,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":36}}
+                      }
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..a7a6b9db832a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { while (x < @@) x += 1; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..0f197cbea8b2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-while-loop-topic-in-loop-head/output.json
@@ -0,0 +1,80 @@
+{
+  "type": "File",
+  "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":38,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":38}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":38,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":38}},
+              "body": [
+                {
+                  "type": "WhileStatement",
+                  "start":14,"end":36,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":36}},
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":21,"end":27,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":27}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":21,"end":22,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":22},"identifierName":"x"},
+                      "name": "x"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "TopicReference",
+                      "start":25,"end":27,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":27}}
+                    }
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":29,"end":36,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":36}},
+                    "expression": {
+                      "type": "AssignmentExpression",
+                      "start":29,"end":35,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":35}},
+                      "operator": "+=",
+                      "left": {
+                        "type": "Identifier",
+                        "start":29,"end":30,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":30},"identifierName":"x"},
+                        "name": "x"
+                      },
+                      "right": {
+                        "type": "NumericLiteral",
+                        "start":34,"end":35,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":35}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-with-block-topic-in-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-with-block-topic-in-body/input.js
new file mode 100644
index 000000000000..4ecdc349dfaf
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-with-block-topic-in-body/input.js
@@ -0,0 +1 @@
+value |> do { with ({}) @@; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-with-block-topic-in-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-with-block-topic-in-body/options.json
new file mode 100644
index 000000000000..5b97f22a11e3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-with-block-topic-in-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-with-block-topic-in-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-with-block-topic-in-body/output.json
new file mode 100644
index 000000000000..4b7b5543bb3b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-do-transform-with-block-topic-in-body/output.json
@@ -0,0 +1,56 @@
+{
+  "type": "File",
+  "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":29,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":29}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":29,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":29}},
+              "body": [
+                {
+                  "type": "WithStatement",
+                  "start":14,"end":27,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":27}},
+                  "object": {
+                    "type": "ObjectExpression",
+                    "start":20,"end":22,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":22}},
+                    "properties": []
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":24,"end":27,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":27}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":24,"end":26,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":26}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-loose-with-topic-first-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-loose-with-topic-first-without-spaces/input.js
new file mode 100644
index 000000000000..5d24fc328c4e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-loose-with-topic-first-without-spaces/input.js
@@ -0,0 +1 @@
+value |> @@==1
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-loose-with-topic-first-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-loose-with-topic-first-without-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-loose-with-topic-first-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-loose-with-topic-first-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-loose-with-topic-first-without-spaces/output.json
new file mode 100644
index 000000000000..98ecc4bca832
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-loose-with-topic-first-without-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":14,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":14}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "==",
+            "right": {
+              "type": "NumericLiteral",
+              "start":13,"end":14,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":14}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-strict-with-topic-first-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-strict-with-topic-first-without-spaces/input.js
new file mode 100644
index 000000000000..fa8a329e21be
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-strict-with-topic-first-without-spaces/input.js
@@ -0,0 +1 @@
+value |> @@===1
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-strict-with-topic-first-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-strict-with-topic-first-without-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-strict-with-topic-first-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-strict-with-topic-first-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-strict-with-topic-first-without-spaces/output.json
new file mode 100644
index 000000000000..0d9b61f0bf65
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-equality-strict-with-topic-first-without-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "===",
+            "right": {
+              "type": "NumericLiteral",
+              "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-with-topic-in-argument/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-with-topic-in-argument/input.js
new file mode 100644
index 000000000000..46c81e85df5c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-with-topic-in-argument/input.js
@@ -0,0 +1 @@
+value |> f(@@)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-with-topic-in-argument/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-with-topic-in-argument/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-with-topic-in-argument/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-with-topic-in-argument/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-with-topic-in-argument/output.json
new file mode 100644
index 000000000000..a2fa21c6ceb7
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-with-topic-in-argument/output.json
@@ -0,0 +1,42 @@
+{
+  "type": "File",
+  "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "CallExpression",
+            "start":9,"end":14,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":14}},
+            "callee": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"f"},
+              "name": "f"
+            },
+            "arguments": [
+              {
+                "type": "TopicReference",
+                "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+              }
+            ]
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-without-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-without-topic/input.js
new file mode 100644
index 000000000000..15a3d7657b9c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-without-topic/input.js
@@ -0,0 +1 @@
+value |> f
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-without-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-without-topic/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-without-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-without-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-without-topic/output.json
new file mode 100644
index 000000000000..3917568d724f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-call-without-topic/output.json
@@ -0,0 +1,35 @@
+{
+  "type": "File",
+  "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "Identifier",
+            "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"f"},
+            "name": "f"
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-another-pipe-in-function-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-another-pipe-in-function-body/input.js
new file mode 100644
index 000000000000..f3f876da0719
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-another-pipe-in-function-body/input.js
@@ -0,0 +1 @@
+x |> function () { @@ |> @@ }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-another-pipe-in-function-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-another-pipe-in-function-body/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-another-pipe-in-function-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-another-pipe-in-function-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-another-pipe-in-function-body/output.json
new file mode 100644
index 000000000000..f81c748e7378
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-another-pipe-in-function-body/output.json
@@ -0,0 +1,59 @@
+{
+  "type": "File",
+  "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "FunctionExpression",
+            "start":5,"end":29,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":29}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BlockStatement",
+              "start":17,"end":29,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":29}},
+              "body": [
+                {
+                  "type": "ExpressionStatement",
+                  "start":19,"end":27,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":27}},
+                  "expression": {
+                    "type": "BinaryExpression",
+                    "start":19,"end":27,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":27}},
+                    "left": {
+                      "type": "TopicReference",
+                      "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}}
+                    },
+                    "operator": "|>",
+                    "right": {
+                      "type": "TopicReference",
+                      "start":25,"end":27,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":27}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-default-parameter/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-default-parameter/input.js
new file mode 100644
index 000000000000..712d044b0e68
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-default-parameter/input.js
@@ -0,0 +1 @@
+value |> function (x = @@) { return x; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-default-parameter/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-default-parameter/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-default-parameter/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-default-parameter/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-default-parameter/output.json
new file mode 100644
index 000000000000..640dfd370737
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-default-parameter/output.json
@@ -0,0 +1,65 @@
+{
+  "type": "File",
+  "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":40}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":40}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":40}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":40}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "FunctionExpression",
+            "start":9,"end":40,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":40}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "AssignmentPattern",
+                "start":19,"end":25,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":25}},
+                "left": {
+                  "type": "Identifier",
+                  "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"x"},
+                  "name": "x"
+                },
+                "right": {
+                  "type": "TopicReference",
+                  "start":23,"end":25,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":25}}
+                }
+              }
+            ],
+            "body": {
+              "type": "BlockStatement",
+              "start":27,"end":40,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":40}},
+              "body": [
+                {
+                  "type": "ReturnStatement",
+                  "start":29,"end":38,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":38}},
+                  "argument": {
+                    "type": "Identifier",
+                    "start":36,"end":37,"loc":{"start":{"line":1,"column":36},"end":{"line":1,"column":37},"identifierName":"x"},
+                    "name": "x"
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-function-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-function-body/input.js
new file mode 100644
index 000000000000..6681fe9d56df
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-function-body/input.js
@@ -0,0 +1 @@
+x |> function () { @@ }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-function-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-function-body/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-function-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-function-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-function-body/output.json
new file mode 100644
index 000000000000..ab81762b5445
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-function-definition-with-topic-in-function-body/output.json
@@ -0,0 +1,50 @@
+{
+  "type": "File",
+  "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "FunctionExpression",
+            "start":5,"end":23,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":23}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BlockStatement",
+              "start":17,"end":23,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":23}},
+              "body": [
+                {
+                  "type": "ExpressionStatement",
+                  "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}},
+                  "expression": {
+                    "type": "TopicReference",
+                    "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}}
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-topic/input.js
new file mode 100644
index 000000000000..a18cbd0f1bb2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-topic/input.js
@@ -0,0 +1 @@
+value |> #
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-topic/options.json
new file mode 100644
index 000000000000..929cd7fdcd6c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-topic/options.json
@@ -0,0 +1,4 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]],
+  "throws": "Invalid topic token #. In order to use # as a topic reference, the pipelineOperator plugin must be configured with { \"proposal\": \"hack\", \"topicToken\": \"#\" }. (1:9)"
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-tuple/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-tuple/input.js
new file mode 100644
index 000000000000..81a3b28d74df
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-tuple/input.js
@@ -0,0 +1,2 @@
+#[0];
+1 |> #[0, @@];
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-tuple/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-tuple/options.json
new file mode 100644
index 000000000000..116be78612f4
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-tuple/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    ["recordAndTuple", { "syntaxType": "hash" }]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-tuple/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-tuple/output.json
new file mode 100644
index 000000000000..4056d03b8c29
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-hash-tuple/output.json
@@ -0,0 +1,69 @@
+{
+  "type": "File",
+  "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5}},
+        "expression": {
+          "type": "TupleExpression",
+          "start":0,"end":4,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":4}},
+          "elements": [
+            {
+              "type": "NumericLiteral",
+              "start":2,"end":3,"loc":{"start":{"line":1,"column":2},"end":{"line":1,"column":3}},
+              "extra": {
+                "rawValue": 0,
+                "raw": "0"
+              },
+              "value": 0
+            }
+          ]
+        }
+      },
+      {
+        "type": "ExpressionStatement",
+        "start":6,"end":20,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":6,"end":19,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":13}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":6,"end":7,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":1}},
+            "extra": {
+              "rawValue": 1,
+              "raw": "1"
+            },
+            "value": 1
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TupleExpression",
+            "start":11,"end":19,"loc":{"start":{"line":2,"column":5},"end":{"line":2,"column":13}},
+            "elements": [
+              {
+                "type": "NumericLiteral",
+                "start":13,"end":14,"loc":{"start":{"line":2,"column":7},"end":{"line":2,"column":8}},
+                "extra": {
+                  "rawValue": 0,
+                  "raw": "0"
+                },
+                "value": 0
+              },
+              {
+                "type": "TopicReference",
+                "start":16,"end":18,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":12}}
+              }
+            ]
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-mixed-pipeline-plugins/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-mixed-pipeline-plugins/input.js
new file mode 100644
index 000000000000..8a575976cf92
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-mixed-pipeline-plugins/input.js
@@ -0,0 +1 @@
+value |> @@
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-mixed-pipeline-plugins/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-mixed-pipeline-plugins/options.json
new file mode 100644
index 000000000000..ee86eb98581c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-mixed-pipeline-plugins/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }], "pipelineOperator"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-mixed-pipeline-plugins/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-mixed-pipeline-plugins/output.json
new file mode 100644
index 000000000000..8b15798610ae
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-mixed-pipeline-plugins/output.json
@@ -0,0 +1,31 @@
+{
+  "type": "File",
+  "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TopicReference",
+            "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-with-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-with-spaces/input.js
new file mode 100644
index 000000000000..344b3a3d0f65
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-with-spaces/input.js
@@ -0,0 +1 @@
+value |> (variable %= @@);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-with-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-with-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-with-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-with-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-with-spaces/output.json
new file mode 100644
index 000000000000..672939df45c5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-with-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":25,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":25}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":10,"end":24,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":24}},
+            "operator": "%=",
+            "left": {
+              "type": "Identifier",
+              "start":10,"end":18,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":18},"identifierName":"variable"},
+              "name": "variable"
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":22,"end":24,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":24}}
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-without-spaces/input.js
new file mode 100644
index 000000000000..0e15a2fb11f0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-without-spaces/input.js
@@ -0,0 +1 @@
+value |> (variable%=@@);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-without-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-without-spaces/output.json
new file mode 100644
index 000000000000..81571e75d3be
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-assignment-without-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":10,"end":22,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":22}},
+            "operator": "%=",
+            "left": {
+              "type": "Identifier",
+              "start":10,"end":18,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":18},"identifierName":"variable"},
+              "name": "variable"
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":20,"end":22,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":22}}
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-regex-outside-pipe/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-regex-outside-pipe/input.js
new file mode 100644
index 000000000000..d2fa335cea9c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-regex-outside-pipe/input.js
@@ -0,0 +1 @@
+5 % /3/g;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-regex-outside-pipe/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-regex-outside-pipe/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-regex-outside-pipe/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-regex-outside-pipe/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-regex-outside-pipe/output.json
new file mode 100644
index 000000000000..b6fb84b72f7c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-regex-outside-pipe/output.json
@@ -0,0 +1,40 @@
+{
+  "type": "File",
+  "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1}},
+            "extra": {
+              "rawValue": 5,
+              "raw": "5"
+            },
+            "value": 5
+          },
+          "operator": "%",
+          "right": {
+            "type": "RegExpLiteral",
+            "start":4,"end":8,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":8}},
+            "extra": {
+              "raw": "/3/g"
+            },
+            "pattern": "3",
+            "flags": "g"
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-with-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-with-spaces/input.js
new file mode 100644
index 000000000000..baef4410dc4f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-with-spaces/input.js
@@ -0,0 +1 @@
+value |> @@ % 2;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-with-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-with-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-with-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-with-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-with-spaces/output.json
new file mode 100644
index 000000000000..092ce0944eb4
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-with-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "%",
+            "right": {
+              "type": "NumericLiteral",
+              "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15}},
+              "extra": {
+                "rawValue": 2,
+                "raw": "2"
+              },
+              "value": 2
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-without-spaces/input.js
new file mode 100644
index 000000000000..3067b26c79ab
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-without-spaces/input.js
@@ -0,0 +1 @@
+value |> @@%2;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-without-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-without-spaces/output.json
new file mode 100644
index 000000000000..2834c23a7607
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-first-without-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":13,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":13}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "%",
+            "right": {
+              "type": "NumericLiteral",
+              "start":12,"end":13,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":13}},
+              "extra": {
+                "rawValue": 2,
+                "raw": "2"
+              },
+              "value": 2
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-with-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-with-spaces/input.js
new file mode 100644
index 000000000000..6c54c280cffc
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-with-spaces/input.js
@@ -0,0 +1 @@
+value |> 2 % @@;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-with-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-with-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-with-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-with-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-with-spaces/output.json
new file mode 100644
index 000000000000..42ca84fed0d1
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-with-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "NumericLiteral",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10}},
+              "extra": {
+                "rawValue": 2,
+                "raw": "2"
+              },
+              "value": 2
+            },
+            "operator": "%",
+            "right": {
+              "type": "TopicReference",
+              "start":13,"end":15,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":15}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-without-spaces/input.js
new file mode 100644
index 000000000000..c3fda482f396
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-without-spaces/input.js
@@ -0,0 +1 @@
+value |> 2%@@;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-without-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-without-spaces/output.json
new file mode 100644
index 000000000000..c56431997313
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-modulo-topic-last-without-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":13,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":13}},
+            "left": {
+              "type": "NumericLiteral",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10}},
+              "extra": {
+                "rawValue": 2,
+                "raw": "2"
+              },
+              "value": 2
+            },
+            "operator": "%",
+            "right": {
+              "type": "TopicReference",
+              "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-with-required-topics/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-with-required-topics/input.js
new file mode 100644
index 000000000000..47daf4d9fa70
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-with-required-topics/input.js
@@ -0,0 +1 @@
+x |> ($ => @@ |> f(@@, $) |> @@ > 1)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-with-required-topics/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-with-required-topics/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-with-required-topics/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-with-required-topics/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-with-required-topics/output.json
new file mode 100644
index 000000000000..c715bce7e7ac
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-with-required-topics/output.json
@@ -0,0 +1,97 @@
+{
+  "type": "File",
+  "start":0,"end":36,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":36}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":36,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":36}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":36,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":36}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":36,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":36}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":6,"end":35,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":35}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"$"},
+                "name": "$"
+              }
+            ],
+            "body": {
+              "type": "BinaryExpression",
+              "start":11,"end":35,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":35}},
+              "left": {
+                "type": "TopicReference",
+                "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+              },
+              "operator": "|>",
+              "right": {
+                "type": "BinaryExpression",
+                "start":17,"end":35,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":35}},
+                "left": {
+                  "type": "CallExpression",
+                  "start":17,"end":25,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":25}},
+                  "callee": {
+                    "type": "Identifier",
+                    "start":17,"end":18,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":18},"identifierName":"f"},
+                    "name": "f"
+                  },
+                  "arguments": [
+                    {
+                      "type": "TopicReference",
+                      "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}}
+                    },
+                    {
+                      "type": "Identifier",
+                      "start":23,"end":24,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":24},"identifierName":"$"},
+                      "name": "$"
+                    }
+                  ]
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "BinaryExpression",
+                  "start":29,"end":35,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":35}},
+                  "left": {
+                    "type": "TopicReference",
+                    "start":29,"end":31,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":31}}
+                  },
+                  "operator": ">",
+                  "right": {
+                    "type": "NumericLiteral",
+                    "start":34,"end":35,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":35}},
+                    "extra": {
+                      "rawValue": 1,
+                      "raw": "1"
+                    },
+                    "value": 1
+                  }
+                }
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-inner-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-inner-topic/input.js
new file mode 100644
index 000000000000..9cd2227016ed
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-inner-topic/input.js
@@ -0,0 +1 @@
+x |> ($ => @@ |> $ + 1)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-inner-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-inner-topic/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-inner-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-inner-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-inner-topic/output.json
new file mode 100644
index 000000000000..d0b6b79bd97e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-inner-topic/output.json
@@ -0,0 +1,76 @@
+{
+  "type": "File",
+  "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:17)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":6,"end":22,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":22}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"$"},
+                "name": "$"
+              }
+            ],
+            "body": {
+              "type": "BinaryExpression",
+              "start":11,"end":22,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":22}},
+              "left": {
+                "type": "TopicReference",
+                "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+              },
+              "operator": "|>",
+              "right": {
+                "type": "BinaryExpression",
+                "start":17,"end":22,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":22}},
+                "left": {
+                  "type": "Identifier",
+                  "start":17,"end":18,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":18},"identifierName":"$"},
+                  "name": "$"
+                },
+                "operator": "+",
+                "right": {
+                  "type": "NumericLiteral",
+                  "start":21,"end":22,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":22}},
+                  "extra": {
+                    "rawValue": 1,
+                    "raw": "1"
+                  },
+                  "value": 1
+                }
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-outer-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-outer-topic/input.js
new file mode 100644
index 000000000000..fe547668995a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-outer-topic/input.js
@@ -0,0 +1 @@
+x |> ($ => $ |> @@)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-outer-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-outer-topic/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-outer-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-outer-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-outer-topic/output.json
new file mode 100644
index 000000000000..e51b8230caeb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-arrow-function-without-outer-topic/output.json
@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:5)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":6,"end":18,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":18}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"$"},
+                "name": "$"
+              }
+            ],
+            "body": {
+              "type": "BinaryExpression",
+              "start":11,"end":18,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":18}},
+              "left": {
+                "type": "Identifier",
+                "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"$"},
+                "name": "$"
+              },
+              "operator": "|>",
+              "right": {
+                "type": "TopicReference",
+                "start":16,"end":18,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":18}}
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-function-call/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-function-call/input.js
new file mode 100644
index 000000000000..57ea178fd817
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-function-call/input.js
@@ -0,0 +1 @@
+x |> (@@ |> f(@@, x))
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-function-call/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-function-call/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-function-call/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-function-call/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-function-call/output.json
new file mode 100644
index 000000000000..9e38a74f8f60
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-with-function-call/output.json
@@ -0,0 +1,60 @@
+{
+  "type": "File",
+  "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":6,"end":20,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":20}},
+            "left": {
+              "type": "TopicReference",
+              "start":6,"end":8,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":8}}
+            },
+            "operator": "|>",
+            "right": {
+              "type": "CallExpression",
+              "start":12,"end":20,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":20}},
+              "callee": {
+                "type": "Identifier",
+                "start":12,"end":13,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":13},"identifierName":"f"},
+                "name": "f"
+              },
+              "arguments": [
+                {
+                  "type": "TopicReference",
+                  "start":14,"end":16,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":16}}
+                },
+                {
+                  "type": "Identifier",
+                  "start":18,"end":19,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":19},"identifierName":"x"},
+                  "name": "x"
+                }
+              ]
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-inner-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-inner-topic/input.js
new file mode 100644
index 000000000000..7e8fde902300
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-inner-topic/input.js
@@ -0,0 +1 @@
+x |> (@@ |> f())
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-inner-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-inner-topic/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-inner-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-inner-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-inner-topic/output.json
new file mode 100644
index 000000000000..8390963fe8c2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-inner-topic/output.json
@@ -0,0 +1,53 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:12)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":6,"end":15,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":6,"end":8,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":8}}
+            },
+            "operator": "|>",
+            "right": {
+              "type": "CallExpression",
+              "start":12,"end":15,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":15}},
+              "callee": {
+                "type": "Identifier",
+                "start":12,"end":13,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":13},"identifierName":"f"},
+                "name": "f"
+              },
+              "arguments": []
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-outer-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-outer-topic/input.js
new file mode 100644
index 000000000000..9d00837048ed
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-outer-topic/input.js
@@ -0,0 +1 @@
+x |> ($ |> f)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-outer-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-outer-topic/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-outer-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-outer-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-outer-topic/output.json
new file mode 100644
index 000000000000..cfab816d1276
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-nested-pipelines-without-outer-topic/output.json
@@ -0,0 +1,50 @@
+{
+  "type": "File",
+  "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:11)",
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:5)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":6,"end":12,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":12}},
+            "left": {
+              "type": "Identifier",
+              "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"$"},
+              "name": "$"
+            },
+            "operator": "|>",
+            "right": {
+              "type": "Identifier",
+              "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"f"},
+              "name": "f"
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-class-expression/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-class-expression/input.js
new file mode 100644
index 000000000000..6ccb6ca13351
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-class-expression/input.js
@@ -0,0 +1 @@
+value |> class { }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-class-expression/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-class-expression/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-class-expression/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-class-expression/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-class-expression/output.json
new file mode 100644
index 000000000000..1e904fe3ddea
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-class-expression/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":9,"end":18,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":18}},
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":15,"end":18,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":18}},
+              "body": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-function-expression/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-function-expression/input.js
new file mode 100644
index 000000000000..faf09879d637
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-function-expression/input.js
@@ -0,0 +1 @@
+value |> function (x) { return; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-function-expression/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-function-expression/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-function-expression/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-function-expression/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-function-expression/output.json
new file mode 100644
index 000000000000..4a5325355978
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-no-topic-function-expression/output.json
@@ -0,0 +1,56 @@
+{
+  "type": "File",
+  "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "FunctionExpression",
+            "start":9,"end":33,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":33}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"x"},
+                "name": "x"
+              }
+            ],
+            "body": {
+              "type": "BlockStatement",
+              "start":22,"end":33,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":33}},
+              "body": [
+                {
+                  "type": "ReturnStatement",
+                  "start":24,"end":31,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":31}},
+                  "argument": null
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-non-generator-yield-identifier/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-non-generator-yield-identifier/input.js
new file mode 100644
index 000000000000..010e5bd09a6d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-non-generator-yield-identifier/input.js
@@ -0,0 +1 @@
+x |> yield + @@;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-non-generator-yield-identifier/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-non-generator-yield-identifier/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-non-generator-yield-identifier/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-non-generator-yield-identifier/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-non-generator-yield-identifier/output.json
new file mode 100644
index 000000000000..fd8b41311ceb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-non-generator-yield-identifier/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":5,"end":15,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "Identifier",
+              "start":5,"end":10,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":10},"identifierName":"yield"},
+              "name": "yield"
+            },
+            "operator": "+",
+            "right": {
+              "type": "TopicReference",
+              "start":13,"end":15,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":15}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-placeholder-template/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-placeholder-template/input.js
new file mode 100644
index 000000000000..15ba69d87479
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-placeholder-template/input.js
@@ -0,0 +1 @@
+@@@@FUNCTION@@@@(0, @@@@VALUE@@@@);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-placeholder-template/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-placeholder-template/options.json
new file mode 100644
index 000000000000..59af753e4300
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-placeholder-template/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    "placeholders"
+  ],
+  "throws": "Cannot combine placeholders plugin and Hack-style pipes."
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-private-property-in-private-method/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-private-property-in-private-method/input.js
new file mode 100644
index 000000000000..dbb7bffaca8a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-private-property-in-private-method/input.js
@@ -0,0 +1,7 @@
+class Thing {
+  #property;
+
+  #method () {
+    value |> this.#property + @@;
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-private-property-in-private-method/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-private-property-in-private-method/options.json
new file mode 100644
index 000000000000..fcd51fb78f2c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-private-property-in-private-method/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    "classPrivateProperties",
+    "classPrivateMethods"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-private-property-in-private-method/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-private-property-in-private-method/output.json
new file mode 100644
index 000000000000..9be0015cd858
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-private-property-in-private-method/output.json
@@ -0,0 +1,111 @@
+{
+  "type": "File",
+  "start":0,"end":82,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":82,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":82,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":11,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":11},"identifierName":"Thing"},
+          "name": "Thing"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":12,"end":82,"loc":{"start":{"line":1,"column":12},"end":{"line":7,"column":1}},
+          "body": [
+            {
+              "type": "ClassPrivateProperty",
+              "start":16,"end":26,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":12}},
+              "static": false,
+              "key": {
+                "type": "PrivateName",
+                "start":16,"end":25,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":11}},
+                "id": {
+                  "type": "Identifier",
+                  "start":17,"end":25,"loc":{"start":{"line":2,"column":3},"end":{"line":2,"column":11},"identifierName":"property"},
+                  "name": "property"
+                }
+              },
+              "value": null
+            },
+            {
+              "type": "ClassPrivateMethod",
+              "start":30,"end":80,"loc":{"start":{"line":4,"column":2},"end":{"line":6,"column":3}},
+              "static": false,
+              "key": {
+                "type": "PrivateName",
+                "start":30,"end":37,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":9}},
+                "id": {
+                  "type": "Identifier",
+                  "start":31,"end":37,"loc":{"start":{"line":4,"column":3},"end":{"line":4,"column":9},"identifierName":"method"},
+                  "name": "method"
+                }
+              },
+              "kind": "method",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [],
+              "body": {
+                "type": "BlockStatement",
+                "start":41,"end":80,"loc":{"start":{"line":4,"column":13},"end":{"line":6,"column":3}},
+                "body": [
+                  {
+                    "type": "ExpressionStatement",
+                    "start":47,"end":76,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":33}},
+                    "expression": {
+                      "type": "BinaryExpression",
+                      "start":47,"end":75,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":32}},
+                      "left": {
+                        "type": "Identifier",
+                        "start":47,"end":52,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":9},"identifierName":"value"},
+                        "name": "value"
+                      },
+                      "operator": "|>",
+                      "right": {
+                        "type": "BinaryExpression",
+                        "start":56,"end":75,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":32}},
+                        "left": {
+                          "type": "MemberExpression",
+                          "start":56,"end":70,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":27}},
+                          "object": {
+                            "type": "ThisExpression",
+                            "start":56,"end":60,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":17}}
+                          },
+                          "computed": false,
+                          "property": {
+                            "type": "PrivateName",
+                            "start":61,"end":70,"loc":{"start":{"line":5,"column":18},"end":{"line":5,"column":27}},
+                            "id": {
+                              "type": "Identifier",
+                              "start":62,"end":70,"loc":{"start":{"line":5,"column":19},"end":{"line":5,"column":27},"identifierName":"property"},
+                              "name": "property"
+                            }
+                          }
+                        },
+                        "operator": "+",
+                        "right": {
+                          "type": "TopicReference",
+                          "start":73,"end":75,"loc":{"start":{"line":5,"column":30},"end":{"line":5,"column":32}}
+                        }
+                      }
+                    }
+                  }
+                ],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-parenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-parenthesized/input.js
new file mode 100644
index 000000000000..868f072fde49
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-parenthesized/input.js
@@ -0,0 +1 @@
+value |> (@@)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-parenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-parenthesized/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-parenthesized/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-parenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-parenthesized/output.json
new file mode 100644
index 000000000000..81a91c7a1330
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-parenthesized/output.json
@@ -0,0 +1,35 @@
+{
+  "type": "File",
+  "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TopicReference",
+            "start":10,"end":12,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":12}},
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-unparenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-unparenthesized/input.js
new file mode 100644
index 000000000000..8a575976cf92
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-unparenthesized/input.js
@@ -0,0 +1 @@
+value |> @@
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-unparenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-unparenthesized/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-unparenthesized/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-unparenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-unparenthesized/output.json
new file mode 100644
index 000000000000..8b15798610ae
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-identity-unparenthesized/output.json
@@ -0,0 +1,31 @@
+{
+  "type": "File",
+  "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TopicReference",
+            "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-then-digit/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-then-digit/input.js
new file mode 100644
index 000000000000..9063e5a9dcb4
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-then-digit/input.js
@@ -0,0 +1 @@
+x |> @@42;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-then-digit/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-then-digit/options.json
new file mode 100644
index 000000000000..c0d9c24a71cd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-then-digit/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "@@"
+      }
+    ]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-then-digit/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-then-digit/output.json
new file mode 100644
index 000000000000..017aba97749b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-then-digit/output.json
@@ -0,0 +1,47 @@
+{
+  "type": "File",
+  "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+  "errors": [
+    "SyntaxError: Missing semicolon. (1:7)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":7,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":7}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":7,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":7}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TopicReference",
+            "start":5,"end":7,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":7}}
+          }
+        }
+      },
+      {
+        "type": "ExpressionStatement",
+        "start":7,"end":10,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":10}},
+        "expression": {
+          "type": "NumericLiteral",
+          "start":7,"end":9,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":9}},
+          "extra": {
+            "rawValue": 42,
+            "raw": "42"
+          },
+          "value": 42
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-with-optional-method-call/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-with-optional-method-call/input.js
new file mode 100644
index 000000000000..49aeabea11a7
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-with-optional-method-call/input.js
@@ -0,0 +1 @@
+value |> @@?.method()
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-with-optional-method-call/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-with-optional-method-call/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-with-optional-method-call/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-with-optional-method-call/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-with-optional-method-call/output.json
new file mode 100644
index 000000000000..57270291759b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-topic-with-optional-method-call/output.json
@@ -0,0 +1,48 @@
+{
+  "type": "File",
+  "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "OptionalCallExpression",
+            "start":9,"end":21,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":21}},
+            "callee": {
+              "type": "OptionalMemberExpression",
+              "start":9,"end":19,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":19}},
+              "object": {
+                "type": "TopicReference",
+                "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+              },
+              "computed": false,
+              "property": {
+                "type": "Identifier",
+                "start":13,"end":19,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":19},"identifierName":"method"},
+                "name": "method"
+              },
+              "optional": true
+            },
+            "optional": false,
+            "arguments": []
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-unbound-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-unbound-topic/input.js
new file mode 100644
index 000000000000..9943e737c61c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-unbound-topic/input.js
@@ -0,0 +1 @@
+1 + @@
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-unbound-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-unbound-topic/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-unbound-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-unbound-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-unbound-topic/output.json
new file mode 100644
index 000000000000..3c7833aaa15c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-unbound-topic/output.json
@@ -0,0 +1,38 @@
+{
+  "type": "File",
+  "start":0,"end":6,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":6}},
+  "errors": [
+    "SyntaxError: Topic reference is unbound; it must be inside a pipe body. (1:4)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":6,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":6}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":6,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":6}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":6,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":6}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1}},
+            "extra": {
+              "rawValue": 1,
+              "raw": "1"
+            },
+            "value": 1
+          },
+          "operator": "+",
+          "right": {
+            "type": "TopicReference",
+            "start":4,"end":6,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":6}}
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-v8intrinsic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-v8intrinsic/input.js
new file mode 100644
index 000000000000..4c6a361dae02
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-v8intrinsic/input.js
@@ -0,0 +1 @@
+%GetOptimizationStatus(f);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-v8intrinsic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-v8intrinsic/options.json
new file mode 100644
index 000000000000..a8302bf05306
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-v8intrinsic/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }],
+    "v8intrinsic"
+  ],
+  "throws": "Cannot combine v8intrinsic plugin and Hack-style pipes."
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-assignment/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-assignment/input.js
new file mode 100644
index 000000000000..64e109fd55ae
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-assignment/input.js
@@ -0,0 +1 @@
+x = 0 |> @@;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-assignment/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-assignment/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-assignment/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-assignment/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-assignment/output.json
new file mode 100644
index 000000000000..2c30399f40cc
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-assignment/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":12,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":12}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":12,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":12}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":12,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":12}},
+        "expression": {
+          "type": "AssignmentExpression",
+          "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+          "operator": "=",
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "right": {
+            "type": "BinaryExpression",
+            "start":4,"end":11,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":11}},
+            "left": {
+              "type": "NumericLiteral",
+              "start":4,"end":5,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":5}},
+              "extra": {
+                "rawValue": 0,
+                "raw": "0"
+              },
+              "value": 0
+            },
+            "operator": "|>",
+            "right": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-classic-for-statement-init/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-classic-for-statement-init/input.js
new file mode 100644
index 000000000000..17b11e6f87f6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-classic-for-statement-init/input.js
@@ -0,0 +1,2 @@
+for (var i = 0 |> @@; i <= 10; i++)
+  sum = sum + i;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-classic-for-statement-init/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-classic-for-statement-init/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-classic-for-statement-init/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-classic-for-statement-init/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-classic-for-statement-init/output.json
new file mode 100644
index 000000000000..060f5e076bcd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-classic-for-statement-init/output.json
@@ -0,0 +1,110 @@
+{
+  "type": "File",
+  "start":0,"end":52,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":52,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ForStatement",
+        "start":0,"end":52,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":16}},
+        "init": {
+          "type": "VariableDeclaration",
+          "start":5,"end":20,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":20}},
+          "declarations": [
+            {
+              "type": "VariableDeclarator",
+              "start":9,"end":20,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":20}},
+              "id": {
+                "type": "Identifier",
+                "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"i"},
+                "name": "i"
+              },
+              "init": {
+                "type": "BinaryExpression",
+                "start":13,"end":20,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":20}},
+                "left": {
+                  "type": "NumericLiteral",
+                  "start":13,"end":14,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":14}},
+                  "extra": {
+                    "rawValue": 0,
+                    "raw": "0"
+                  },
+                  "value": 0
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "TopicReference",
+                  "start":18,"end":20,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":20}}
+                }
+              }
+            }
+          ],
+          "kind": "var"
+        },
+        "test": {
+          "type": "BinaryExpression",
+          "start":22,"end":29,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":29}},
+          "left": {
+            "type": "Identifier",
+            "start":22,"end":23,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":23},"identifierName":"i"},
+            "name": "i"
+          },
+          "operator": "<=",
+          "right": {
+            "type": "NumericLiteral",
+            "start":27,"end":29,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":29}},
+            "extra": {
+              "rawValue": 10,
+              "raw": "10"
+            },
+            "value": 10
+          }
+        },
+        "update": {
+          "type": "UpdateExpression",
+          "start":31,"end":34,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":34}},
+          "operator": "++",
+          "prefix": false,
+          "argument": {
+            "type": "Identifier",
+            "start":31,"end":32,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":32},"identifierName":"i"},
+            "name": "i"
+          }
+        },
+        "body": {
+          "type": "ExpressionStatement",
+          "start":38,"end":52,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":16}},
+          "expression": {
+            "type": "AssignmentExpression",
+            "start":38,"end":51,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":15}},
+            "operator": "=",
+            "left": {
+              "type": "Identifier",
+              "start":38,"end":41,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":5},"identifierName":"sum"},
+              "name": "sum"
+            },
+            "right": {
+              "type": "BinaryExpression",
+              "start":44,"end":51,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":15}},
+              "left": {
+                "type": "Identifier",
+                "start":44,"end":47,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":11},"identifierName":"sum"},
+                "name": "sum"
+              },
+              "operator": "+",
+              "right": {
+                "type": "Identifier",
+                "start":50,"end":51,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":15},"identifierName":"i"},
+                "name": "i"
+              }
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-with-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-with-spaces/input.js
new file mode 100644
index 000000000000..a7badd053692
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-with-spaces/input.js
@@ -0,0 +1 @@
+variable %= value |> @@;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-with-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-with-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-with-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-with-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-with-spaces/output.json
new file mode 100644
index 000000000000..b29a05daa578
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-with-spaces/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+        "expression": {
+          "type": "AssignmentExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "operator": "%=",
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8},"identifierName":"variable"},
+            "name": "variable"
+          },
+          "right": {
+            "type": "BinaryExpression",
+            "start":12,"end":23,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":23}},
+            "left": {
+              "type": "Identifier",
+              "start":12,"end":17,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":17},"identifierName":"value"},
+              "name": "value"
+            },
+            "operator": "|>",
+            "right": {
+              "type": "TopicReference",
+              "start":21,"end":23,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":23}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-without-spaces/input.js
new file mode 100644
index 000000000000..7eaf2543239b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-without-spaces/input.js
@@ -0,0 +1 @@
+variable%=value |> @@;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-without-spaces/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-without-spaces/output.json
new file mode 100644
index 000000000000..e06d1258b946
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-modulo-assignment-without-spaces/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
+        "expression": {
+          "type": "AssignmentExpression",
+          "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+          "operator": "%=",
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8},"identifierName":"variable"},
+            "name": "variable"
+          },
+          "right": {
+            "type": "BinaryExpression",
+            "start":10,"end":21,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":21}},
+            "left": {
+              "type": "Identifier",
+              "start":10,"end":15,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":15},"identifierName":"value"},
+              "name": "value"
+            },
+            "operator": "|>",
+            "right": {
+              "type": "TopicReference",
+              "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-variable-declaration/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-variable-declaration/input.js
new file mode 100644
index 000000000000..c36d96442df1
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-variable-declaration/input.js
@@ -0,0 +1 @@
+const x = 0 |> @@;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-variable-declaration/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-variable-declaration/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-variable-declaration/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-variable-declaration/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-variable-declaration/output.json
new file mode 100644
index 000000000000..2142f35fc204
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-within-variable-declaration/output.json
@@ -0,0 +1,47 @@
+{
+  "type": "File",
+  "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start":6,"end":17,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":17}},
+            "id": {
+              "type": "Identifier",
+              "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"x"},
+              "name": "x"
+            },
+            "init": {
+              "type": "BinaryExpression",
+              "start":10,"end":17,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":17}},
+              "left": {
+                "type": "NumericLiteral",
+                "start":10,"end":11,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":11}},
+                "extra": {
+                  "rawValue": 0,
+                  "raw": "0"
+                },
+                "value": 0
+              },
+              "operator": "|>",
+              "right": {
+                "type": "TopicReference",
+                "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17}}
+              }
+            }
+          }
+        ],
+        "kind": "const"
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-parenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-parenthesized/input.js
new file mode 100644
index 000000000000..d6c413a4382e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-parenthesized/input.js
@@ -0,0 +1,3 @@
+function * f (x) {
+  return x |> (yield @@);
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-parenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-parenthesized/options.json
new file mode 100644
index 000000000000..7d78ef60d1b8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-parenthesized/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-parenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-parenthesized/output.json
new file mode 100644
index 000000000000..ce25fc689b94
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-parenthesized/output.json
@@ -0,0 +1,65 @@
+{
+  "type": "File",
+  "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"f"},
+          "name": "f"
+        },
+        "generator": true,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15},"identifierName":"x"},
+            "name": "x"
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":17,"end":46,"loc":{"start":{"line":1,"column":17},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ReturnStatement",
+              "start":21,"end":44,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":25}},
+              "argument": {
+                "type": "BinaryExpression",
+                "start":28,"end":43,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":24}},
+                "left": {
+                  "type": "Identifier",
+                  "start":28,"end":29,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":10},"identifierName":"x"},
+                  "name": "x"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "YieldExpression",
+                  "start":34,"end":42,"loc":{"start":{"line":2,"column":15},"end":{"line":2,"column":23}},
+                  "delegate": false,
+                  "argument": {
+                    "type": "TopicReference",
+                    "start":40,"end":42,"loc":{"start":{"line":2,"column":21},"end":{"line":2,"column":23}}
+                  },
+                  "extra": {
+                    "parenthesized": true,
+                    "parenStart": 33
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-unparenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-unparenthesized/input.js
new file mode 100644
index 000000000000..5754b98a8885
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-unparenthesized/input.js
@@ -0,0 +1,3 @@
+function * f (x) {
+  return x |> yield @@;
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-unparenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-unparenthesized/options.json
new file mode 100644
index 000000000000..0dfb1fc3aa49
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-unparenthesized/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "@@"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-unparenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-unparenthesized/output.json
new file mode 100644
index 000000000000..09bad13154b3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-generator-unparenthesized/output.json
@@ -0,0 +1,64 @@
+{
+  "type": "File",
+  "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized yield expression; please wrap it in parentheses. (2:14)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"f"},
+          "name": "f"
+        },
+        "generator": true,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15},"identifierName":"x"},
+            "name": "x"
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":17,"end":44,"loc":{"start":{"line":1,"column":17},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ReturnStatement",
+              "start":21,"end":42,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":23}},
+              "argument": {
+                "type": "BinaryExpression",
+                "start":28,"end":41,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":22}},
+                "left": {
+                  "type": "Identifier",
+                  "start":28,"end":29,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":10},"identifierName":"x"},
+                  "name": "x"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "YieldExpression",
+                  "start":33,"end":41,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":22}},
+                  "delegate": false,
+                  "argument": {
+                    "type": "TopicReference",
+                    "start":39,"end":41,"loc":{"start":{"line":2,"column":20},"end":{"line":2,"column":22}}
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-identifier-unparenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-identifier-unparenthesized/input.js
new file mode 100644
index 000000000000..010e5bd09a6d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-identifier-unparenthesized/input.js
@@ -0,0 +1 @@
+x |> yield + @@;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-identifier-unparenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-identifier-unparenthesized/options.json
new file mode 100644
index 000000000000..c0d9c24a71cd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-identifier-unparenthesized/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "@@"
+      }
+    ]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-identifier-unparenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-identifier-unparenthesized/output.json
new file mode 100644
index 000000000000..fd8b41311ceb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-at-proposal-yield-identifier-unparenthesized/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":5,"end":15,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "Identifier",
+              "start":5,"end":10,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":10},"identifierName":"yield"},
+              "name": "yield"
+            },
+            "operator": "+",
+            "right": {
+              "type": "TopicReference",
+              "start":13,"end":15,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":15}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-first/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-first/input.js
new file mode 100644
index 000000000000..cf13f13394d6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-first/input.js
@@ -0,0 +1 @@
+value |> ^^ + 1
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-first/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-first/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-first/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-first/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-first/output.json
new file mode 100644
index 000000000000..14a12f4fc9ad
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-first/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "+",
+            "right": {
+              "type": "NumericLiteral",
+              "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-last/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-last/input.js
new file mode 100644
index 000000000000..64774874bd7f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-last/input.js
@@ -0,0 +1 @@
+value |> 1 + ^^
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-last/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-last/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-last/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-last/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-last/output.json
new file mode 100644
index 000000000000..64f362be927d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-with-topic-last/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "NumericLiteral",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            },
+            "operator": "+",
+            "right": {
+              "type": "TopicReference",
+              "start":13,"end":15,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":15}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-without-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-without-topic/input.js
new file mode 100644
index 000000000000..e952adac15fd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-without-topic/input.js
@@ -0,0 +1 @@
+value |> a + b
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-without-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-without-topic/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-without-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-without-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-without-topic/output.json
new file mode 100644
index 000000000000..6565ae6d9aa2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-addition-without-topic/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":14,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":14}},
+            "left": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"a"},
+              "name": "a"
+            },
+            "operator": "+",
+            "right": {
+              "type": "Identifier",
+              "start":13,"end":14,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":14},"identifierName":"b"},
+              "name": "b"
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-parenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-parenthesized/input.js
new file mode 100644
index 000000000000..6bf6ad3b7886
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-parenthesized/input.js
@@ -0,0 +1 @@
+value |> (() => ^^ + 1)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-parenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-parenthesized/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-parenthesized/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-parenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-parenthesized/output.json
new file mode 100644
index 000000000000..5e034e6dee57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-parenthesized/output.json
@@ -0,0 +1,57 @@
+{
+  "type": "File",
+  "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":10,"end":22,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":22}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BinaryExpression",
+              "start":16,"end":22,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":22}},
+              "left": {
+                "type": "TopicReference",
+                "start":16,"end":18,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":18}}
+              },
+              "operator": "+",
+              "right": {
+                "type": "NumericLiteral",
+                "start":21,"end":22,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":22}},
+                "extra": {
+                  "rawValue": 1,
+                  "raw": "1"
+                },
+                "value": 1
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-unparenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-unparenthesized/input.js
new file mode 100644
index 000000000000..2b9bda557a97
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-unparenthesized/input.js
@@ -0,0 +1 @@
+10 |> x => x + ^^;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-unparenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-unparenthesized/options.json
new file mode 100644
index 000000000000..ae184a44d3d5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-unparenthesized/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "^^"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-unparenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-unparenthesized/output.json
new file mode 100644
index 000000000000..8266a4927101
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-arrow-function-unparenthesized/output.json
@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized arrow function expression; please wrap it in parentheses. (1:6)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":2,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":2}},
+            "extra": {
+              "rawValue": 10,
+              "raw": "10"
+            },
+            "value": 10
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":6,"end":17,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":17}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"x"},
+                "name": "x"
+              }
+            ],
+            "body": {
+              "type": "BinaryExpression",
+              "start":11,"end":17,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":17}},
+              "left": {
+                "type": "Identifier",
+                "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"x"},
+                "name": "x"
+              },
+              "operator": "+",
+              "right": {
+                "type": "TopicReference",
+                "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17}}
+              }
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-logical-and/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-logical-and/input.js
new file mode 100644
index 000000000000..d86ba27b5fb6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-logical-and/input.js
@@ -0,0 +1 @@
+value |> x &&= ^^
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-logical-and/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-logical-and/options.json
new file mode 100644
index 000000000000..ae184a44d3d5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-logical-and/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "^^"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-logical-and/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-logical-and/output.json
new file mode 100644
index 000000000000..e3d61d042cdb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-logical-and/output.json
@@ -0,0 +1,44 @@
+{
+  "type": "File",
+  "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized assignment expression; please wrap it in parentheses. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":9,"end":17,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":17}},
+            "operator": "&&=",
+            "left": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"x"},
+              "name": "x"
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-normal/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-normal/input.js
new file mode 100644
index 000000000000..69886af44e4a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-normal/input.js
@@ -0,0 +1 @@
+value |> [x, y] = ^^
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-normal/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-normal/options.json
new file mode 100644
index 000000000000..ae184a44d3d5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-normal/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "^^"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-normal/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-normal/output.json
new file mode 100644
index 000000000000..4e13d17f8b5e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-normal/output.json
@@ -0,0 +1,55 @@
+{
+  "type": "File",
+  "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized assignment expression; please wrap it in parentheses. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":9,"end":20,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":20}},
+            "operator": "=",
+            "left": {
+              "type": "ArrayPattern",
+              "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+              "elements": [
+                {
+                  "type": "Identifier",
+                  "start":10,"end":11,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":11},"identifierName":"x"},
+                  "name": "x"
+                },
+                {
+                  "type": "Identifier",
+                  "start":13,"end":14,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":14},"identifierName":"y"},
+                  "name": "y"
+                }
+              ]
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":18,"end":20,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":20}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-plus/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-plus/input.js
new file mode 100644
index 000000000000..69f15199278b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-plus/input.js
@@ -0,0 +1 @@
+value |> x += ^^
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-plus/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-plus/options.json
new file mode 100644
index 000000000000..ae184a44d3d5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-plus/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "^^"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-plus/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-plus/output.json
new file mode 100644
index 000000000000..8f65e60606a5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-plus/output.json
@@ -0,0 +1,44 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized assignment expression; please wrap it in parentheses. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":9,"end":16,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":16}},
+            "operator": "+=",
+            "left": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"x"},
+              "name": "x"
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":14,"end":16,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":16}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-to-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-to-topic/input.js
new file mode 100644
index 000000000000..08d370210a2c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-to-topic/input.js
@@ -0,0 +1 @@
+value |> (^^ = 1);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-to-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-to-topic/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-to-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-to-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-to-topic/output.json
new file mode 100644
index 000000000000..1c0352cc28cb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-assignment-to-topic/output.json
@@ -0,0 +1,52 @@
+{
+  "type": "File",
+  "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+  "errors": [
+    "SyntaxError: Invalid left-hand side in assignment expression. (1:10)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":17,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":17}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":10,"end":16,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":16}},
+            "operator": "=",
+            "left": {
+              "type": "TopicReference",
+              "start":10,"end":12,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":12}}
+            },
+            "right": {
+              "type": "NumericLiteral",
+              "start":15,"end":16,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":16}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-associativity/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-associativity/input.js
new file mode 100644
index 000000000000..1393e755cf04
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-associativity/input.js
@@ -0,0 +1 @@
+1 |> f(^^) |> g(^^);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-associativity/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-associativity/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-associativity/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-associativity/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-associativity/output.json
new file mode 100644
index 000000000000..db7ebf40c8f2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-associativity/output.json
@@ -0,0 +1,66 @@
+{
+  "type": "File",
+  "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":20}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1}},
+            "extra": {
+              "rawValue": 1,
+              "raw": "1"
+            },
+            "value": 1
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":5,"end":19,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":19}},
+            "left": {
+              "type": "CallExpression",
+              "start":5,"end":10,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":10}},
+              "callee": {
+                "type": "Identifier",
+                "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"f"},
+                "name": "f"
+              },
+              "arguments": [
+                {
+                  "type": "TopicReference",
+                  "start":7,"end":9,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":9}}
+                }
+              ]
+            },
+            "operator": "|>",
+            "right": {
+              "type": "CallExpression",
+              "start":14,"end":19,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":19}},
+              "callee": {
+                "type": "Identifier",
+                "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15},"identifierName":"g"},
+                "name": "g"
+              },
+              "arguments": [
+                {
+                  "type": "TopicReference",
+                  "start":16,"end":18,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":18}}
+                }
+              ]
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-async-await/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-async-await/input.js
new file mode 100644
index 000000000000..bf04b785006e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-async-await/input.js
@@ -0,0 +1,3 @@
+async function f () {
+  return x |> await ^^;
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-async-await/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-async-await/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-async-await/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-async-await/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-async-await/output.json
new file mode 100644
index 000000000000..9c6d1e74bd5b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-async-await/output.json
@@ -0,0 +1,54 @@
+{
+  "type": "File",
+  "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":16,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":16},"identifierName":"f"},
+          "name": "f"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":20,"end":47,"loc":{"start":{"line":1,"column":20},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ReturnStatement",
+              "start":24,"end":45,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":23}},
+              "argument": {
+                "type": "BinaryExpression",
+                "start":31,"end":44,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":22}},
+                "left": {
+                  "type": "Identifier",
+                  "start":31,"end":32,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":10},"identifierName":"x"},
+                  "name": "x"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "AwaitExpression",
+                  "start":36,"end":44,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":22}},
+                  "argument": {
+                    "type": "TopicReference",
+                    "start":42,"end":44,"loc":{"start":{"line":2,"column":20},"end":{"line":2,"column":22}}
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-bare-identifier/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-bare-identifier/input.js
new file mode 100644
index 000000000000..b9753fe61125
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-bare-identifier/input.js
@@ -0,0 +1 @@
+value |> @foo class { constructor () { ^^; } }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-bare-identifier/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-bare-identifier/options.json
new file mode 100644
index 000000000000..5ba6fd121df6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-bare-identifier/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    ["decorators", { "decoratorsBeforeExport": false }]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-bare-identifier/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-bare-identifier/output.json
new file mode 100644
index 000000000000..65e2053d6f2a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-bare-identifier/output.json
@@ -0,0 +1,81 @@
+{
+  "type": "File",
+  "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":9,"end":46,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":46}},
+            "decorators": [
+              {
+                "type": "Decorator",
+                "start":9,"end":13,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":13}},
+                "expression": {
+                  "type": "Identifier",
+                  "start":10,"end":13,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":13},"identifierName":"foo"},
+                  "name": "foo"
+                }
+              }
+            ],
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":20,"end":46,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":46}},
+              "body": [
+                {
+                  "type": "ClassMethod",
+                  "start":22,"end":44,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":44}},
+                  "static": false,
+                  "key": {
+                    "type": "Identifier",
+                    "start":22,"end":33,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":33},"identifierName":"constructor"},
+                    "name": "constructor"
+                  },
+                  "computed": false,
+                  "kind": "constructor",
+                  "id": null,
+                  "generator": false,
+                  "async": false,
+                  "params": [],
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":44,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":44}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":39,"end":42,"loc":{"start":{"line":1,"column":39},"end":{"line":1,"column":42}},
+                        "expression": {
+                          "type": "TopicReference",
+                          "start":39,"end":41,"loc":{"start":{"line":1,"column":39},"end":{"line":1,"column":41}}
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-identifier/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-identifier/input.js
new file mode 100644
index 000000000000..ae4455ff35bc
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-identifier/input.js
@@ -0,0 +1 @@
+value |> @(foo) class { constructor () { ^^; } }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-identifier/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-identifier/options.json
new file mode 100644
index 000000000000..5ba6fd121df6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-identifier/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    ["decorators", { "decoratorsBeforeExport": false }]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-identifier/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-identifier/output.json
new file mode 100644
index 000000000000..06455b0c8955
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-identifier/output.json
@@ -0,0 +1,81 @@
+{
+  "type": "File",
+  "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":48}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":48}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":48}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":48,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":48}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":9,"end":48,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":48}},
+            "decorators": [
+              {
+                "type": "Decorator",
+                "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+                "expression": {
+                  "type": "Identifier",
+                  "start":11,"end":14,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":14},"identifierName":"foo"},
+                  "name": "foo"
+                }
+              }
+            ],
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":22,"end":48,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":48}},
+              "body": [
+                {
+                  "type": "ClassMethod",
+                  "start":24,"end":46,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":46}},
+                  "static": false,
+                  "key": {
+                    "type": "Identifier",
+                    "start":24,"end":35,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":35},"identifierName":"constructor"},
+                    "name": "constructor"
+                  },
+                  "computed": false,
+                  "kind": "constructor",
+                  "id": null,
+                  "generator": false,
+                  "async": false,
+                  "params": [],
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":39,"end":46,"loc":{"start":{"line":1,"column":39},"end":{"line":1,"column":46}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":41,"end":44,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":44}},
+                        "expression": {
+                          "type": "TopicReference",
+                          "start":41,"end":43,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":43}}
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-topic/input.js
new file mode 100644
index 000000000000..0f36376fdf7f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-topic/input.js
@@ -0,0 +1 @@
+value |> @(^^) class {}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-topic/options.json
new file mode 100644
index 000000000000..5ba6fd121df6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-topic/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    ["decorators", { "decoratorsBeforeExport": false }]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-topic/output.json
new file mode 100644
index 000000000000..66492e7e5519
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-decorator-with-parenthesized-topic/output.json
@@ -0,0 +1,48 @@
+{
+  "type": "File",
+  "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":9,"end":23,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":23}},
+            "decorators": [
+              {
+                "type": "Decorator",
+                "start":9,"end":14,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":14}},
+                "expression": {
+                  "type": "TopicReference",
+                  "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+                }
+              }
+            ],
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":21,"end":23,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":23}},
+              "body": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-with-private-property/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-with-private-property/input.js
new file mode 100644
index 000000000000..552689be78bd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-with-private-property/input.js
@@ -0,0 +1,7 @@
+value |> new (class Thing {
+  #property;
+
+  method () {
+    return ^^ + this.#property;
+  }
+});
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-with-private-property/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-with-private-property/options.json
new file mode 100644
index 000000000000..77d2746d0ac0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-with-private-property/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    "classPrivateProperties",
+    "classPrivateMethods"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-with-private-property/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-with-private-property/output.json
new file mode 100644
index 000000000000..5e32fe170d3e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-with-private-property/output.json
@@ -0,0 +1,121 @@
+{
+  "type": "File",
+  "start":0,"end":95,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":3}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":95,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":3}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":95,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":3}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":94,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":2}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "NewExpression",
+            "start":9,"end":94,"loc":{"start":{"line":1,"column":9},"end":{"line":7,"column":2}},
+            "callee": {
+              "type": "ClassExpression",
+              "start":14,"end":93,"loc":{"start":{"line":1,"column":14},"end":{"line":7,"column":1}},
+              "id": {
+                "type": "Identifier",
+                "start":20,"end":25,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":25},"identifierName":"Thing"},
+                "name": "Thing"
+              },
+              "superClass": null,
+              "body": {
+                "type": "ClassBody",
+                "start":26,"end":93,"loc":{"start":{"line":1,"column":26},"end":{"line":7,"column":1}},
+                "body": [
+                  {
+                    "type": "ClassPrivateProperty",
+                    "start":30,"end":40,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":12}},
+                    "static": false,
+                    "key": {
+                      "type": "PrivateName",
+                      "start":30,"end":39,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":11}},
+                      "id": {
+                        "type": "Identifier",
+                        "start":31,"end":39,"loc":{"start":{"line":2,"column":3},"end":{"line":2,"column":11},"identifierName":"property"},
+                        "name": "property"
+                      }
+                    },
+                    "value": null
+                  },
+                  {
+                    "type": "ClassMethod",
+                    "start":44,"end":91,"loc":{"start":{"line":4,"column":2},"end":{"line":6,"column":3}},
+                    "static": false,
+                    "key": {
+                      "type": "Identifier",
+                      "start":44,"end":50,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":8},"identifierName":"method"},
+                      "name": "method"
+                    },
+                    "computed": false,
+                    "kind": "method",
+                    "id": null,
+                    "generator": false,
+                    "async": false,
+                    "params": [],
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":54,"end":91,"loc":{"start":{"line":4,"column":12},"end":{"line":6,"column":3}},
+                      "body": [
+                        {
+                          "type": "ReturnStatement",
+                          "start":60,"end":87,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":31}},
+                          "argument": {
+                            "type": "BinaryExpression",
+                            "start":67,"end":86,"loc":{"start":{"line":5,"column":11},"end":{"line":5,"column":30}},
+                            "left": {
+                              "type": "TopicReference",
+                              "start":67,"end":69,"loc":{"start":{"line":5,"column":11},"end":{"line":5,"column":13}}
+                            },
+                            "operator": "+",
+                            "right": {
+                              "type": "MemberExpression",
+                              "start":72,"end":86,"loc":{"start":{"line":5,"column":16},"end":{"line":5,"column":30}},
+                              "object": {
+                                "type": "ThisExpression",
+                                "start":72,"end":76,"loc":{"start":{"line":5,"column":16},"end":{"line":5,"column":20}}
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "PrivateName",
+                                "start":77,"end":86,"loc":{"start":{"line":5,"column":21},"end":{"line":5,"column":30}},
+                                "id": {
+                                  "type": "Identifier",
+                                  "start":78,"end":86,"loc":{"start":{"line":5,"column":22},"end":{"line":5,"column":30},"identifierName":"property"},
+                                  "name": "property"
+                                }
+                              }
+                            }
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  }
+                ]
+              },
+              "extra": {
+                "parenthesized": true,
+                "parenStart": 13
+              }
+            },
+            "arguments": []
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-without-private-property/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-without-private-property/input.js
new file mode 100644
index 000000000000..25d456544a7c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-without-private-property/input.js
@@ -0,0 +1 @@
+x |> class { constructor () { this.x = ^^; } }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-without-private-property/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-without-private-property/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-without-private-property/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-without-private-property/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-without-private-property/output.json
new file mode 100644
index 000000000000..6673187ad7a5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-class-expression-without-private-property/output.json
@@ -0,0 +1,89 @@
+{
+  "type": "File",
+  "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":5,"end":46,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":46}},
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":11,"end":46,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":46}},
+              "body": [
+                {
+                  "type": "ClassMethod",
+                  "start":13,"end":44,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":44}},
+                  "static": false,
+                  "key": {
+                    "type": "Identifier",
+                    "start":13,"end":24,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":24},"identifierName":"constructor"},
+                    "name": "constructor"
+                  },
+                  "computed": false,
+                  "kind": "constructor",
+                  "id": null,
+                  "generator": false,
+                  "async": false,
+                  "params": [],
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":28,"end":44,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":44}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":30,"end":42,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":42}},
+                        "expression": {
+                          "type": "AssignmentExpression",
+                          "start":30,"end":41,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":41}},
+                          "operator": "=",
+                          "left": {
+                            "type": "MemberExpression",
+                            "start":30,"end":36,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":36}},
+                            "object": {
+                              "type": "ThisExpression",
+                              "start":30,"end":34,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":34}}
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":35,"end":36,"loc":{"start":{"line":1,"column":35},"end":{"line":1,"column":36},"identifierName":"x"},
+                              "name": "x"
+                            }
+                          },
+                          "right": {
+                            "type": "TopicReference",
+                            "start":39,"end":41,"loc":{"start":{"line":1,"column":39},"end":{"line":1,"column":41}}
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ]
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-comma-topic-pair/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-comma-topic-pair/input.js
new file mode 100644
index 000000000000..29bfaba15992
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-comma-topic-pair/input.js
@@ -0,0 +1 @@
+10 |> (^^, ^^);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-comma-topic-pair/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-comma-topic-pair/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-comma-topic-pair/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-comma-topic-pair/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-comma-topic-pair/output.json
new file mode 100644
index 000000000000..07c3718a305e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-comma-topic-pair/output.json
@@ -0,0 +1,49 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":2,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":2}},
+            "extra": {
+              "rawValue": 10,
+              "raw": "10"
+            },
+            "value": 10
+          },
+          "operator": "|>",
+          "right": {
+            "type": "SequenceExpression",
+            "start":7,"end":13,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":13}},
+            "expressions": [
+              {
+                "type": "TopicReference",
+                "start":7,"end":9,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":9}}
+              },
+              {
+                "type": "TopicReference",
+                "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+              }
+            ],
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 6
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-computed-no-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-computed-no-topic/input.js
new file mode 100644
index 000000000000..5a02dee8ec60
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-computed-no-topic/input.js
@@ -0,0 +1 @@
+value |> a[b]
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-computed-no-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-computed-no-topic/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-computed-no-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-computed-no-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-computed-no-topic/output.json
new file mode 100644
index 000000000000..3959a09863b0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-computed-no-topic/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "MemberExpression",
+            "start":9,"end":13,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":13}},
+            "object": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"a"},
+              "name": "a"
+            },
+            "computed": true,
+            "property": {
+              "type": "Identifier",
+              "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"b"},
+              "name": "b"
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-division/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-division/input.js
new file mode 100644
index 000000000000..4ad75cd85778
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-division/input.js
@@ -0,0 +1 @@
+value |> ^^ / 2
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-division/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-division/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-division/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-division/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-division/output.json
new file mode 100644
index 000000000000..b270f10daff6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-division/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "/",
+            "right": {
+              "type": "NumericLiteral",
+              "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15}},
+              "extra": {
+                "rawValue": 2,
+                "raw": "2"
+              },
+              "value": 2
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..483882381f09
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { do x += ^^; while (x < 50); }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..941f2f506218
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,80 @@
+{
+  "type": "File",
+  "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":43,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":43}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":43,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":43}},
+              "body": [
+                {
+                  "type": "DoWhileStatement",
+                  "start":14,"end":41,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":41}},
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":17,"end":25,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":25}},
+                    "expression": {
+                      "type": "AssignmentExpression",
+                      "start":17,"end":24,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":24}},
+                      "operator": "+=",
+                      "left": {
+                        "type": "Identifier",
+                        "start":17,"end":18,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":18},"identifierName":"x"},
+                        "name": "x"
+                      },
+                      "right": {
+                        "type": "TopicReference",
+                        "start":22,"end":24,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":24}}
+                      }
+                    }
+                  },
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":33,"end":39,"loc":{"start":{"line":1,"column":33},"end":{"line":1,"column":39}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":33,"end":34,"loc":{"start":{"line":1,"column":33},"end":{"line":1,"column":34},"identifierName":"x"},
+                      "name": "x"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "NumericLiteral",
+                      "start":37,"end":39,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":39}},
+                      "extra": {
+                        "rawValue": 50,
+                        "raw": "50"
+                      },
+                      "value": 50
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..ab8054321160
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { do x += 1; while (x < ^^); }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..19a23bc8d0a9
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-do-while-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,80 @@
+{
+  "type": "File",
+  "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":42}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":42}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":42}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":42}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":42,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":42}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":42,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":42}},
+              "body": [
+                {
+                  "type": "DoWhileStatement",
+                  "start":14,"end":40,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":40}},
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":17,"end":24,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":24}},
+                    "expression": {
+                      "type": "AssignmentExpression",
+                      "start":17,"end":23,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":23}},
+                      "operator": "+=",
+                      "left": {
+                        "type": "Identifier",
+                        "start":17,"end":18,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":18},"identifierName":"x"},
+                        "name": "x"
+                      },
+                      "right": {
+                        "type": "NumericLiteral",
+                        "start":22,"end":23,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":23}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    }
+                  },
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":32,"end":38,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":38}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":32,"end":33,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":33},"identifierName":"x"},
+                      "name": "x"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "TopicReference",
+                      "start":36,"end":38,"loc":{"start":{"line":1,"column":36},"end":{"line":1,"column":38}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..713a2f9da3a3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1,3 @@
+async function af () {
+  value |> do { for await (const e of sequence) ^^; }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..d96bb6647ab0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    "doExpressions"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..fddba25fc5fe
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,93 @@
+{
+  "type": "File",
+  "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17},"identifierName":"af"},
+          "name": "af"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":21,"end":78,"loc":{"start":{"line":1,"column":21},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":25,"end":76,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":53}},
+              "expression": {
+                "type": "BinaryExpression",
+                "start":25,"end":76,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":53}},
+                "left": {
+                  "type": "Identifier",
+                  "start":25,"end":30,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":7},"identifierName":"value"},
+                  "name": "value"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "DoExpression",
+                  "start":34,"end":76,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":53}},
+                  "async": false,
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":76,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":53}},
+                    "body": [
+                      {
+                        "type": "ForOfStatement",
+                        "start":39,"end":74,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":51}},
+                        "await": true,
+                        "left": {
+                          "type": "VariableDeclaration",
+                          "start":50,"end":57,"loc":{"start":{"line":2,"column":27},"end":{"line":2,"column":34}},
+                          "declarations": [
+                            {
+                              "type": "VariableDeclarator",
+                              "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34}},
+                              "id": {
+                                "type": "Identifier",
+                                "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"e"},
+                                "name": "e"
+                              },
+                              "init": null
+                            }
+                          ],
+                          "kind": "const"
+                        },
+                        "right": {
+                          "type": "Identifier",
+                          "start":61,"end":69,"loc":{"start":{"line":2,"column":38},"end":{"line":2,"column":46},"identifierName":"sequence"},
+                          "name": "sequence"
+                        },
+                        "body": {
+                          "type": "ExpressionStatement",
+                          "start":71,"end":74,"loc":{"start":{"line":2,"column":48},"end":{"line":2,"column":51}},
+                          "expression": {
+                            "type": "TopicReference",
+                            "start":71,"end":73,"loc":{"start":{"line":2,"column":48},"end":{"line":2,"column":50}}
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..132c5f9c1644
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1,3 @@
+async function af () {
+  value |> do { for await (const e of ^^) e; }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..d96bb6647ab0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    "doExpressions"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..4f5624112439
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,93 @@
+{
+  "type": "File",
+  "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17},"identifierName":"af"},
+          "name": "af"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":21,"end":71,"loc":{"start":{"line":1,"column":21},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":25,"end":69,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":46}},
+              "expression": {
+                "type": "BinaryExpression",
+                "start":25,"end":69,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":46}},
+                "left": {
+                  "type": "Identifier",
+                  "start":25,"end":30,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":7},"identifierName":"value"},
+                  "name": "value"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "DoExpression",
+                  "start":34,"end":69,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":46}},
+                  "async": false,
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":69,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":46}},
+                    "body": [
+                      {
+                        "type": "ForOfStatement",
+                        "start":39,"end":67,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":44}},
+                        "await": true,
+                        "left": {
+                          "type": "VariableDeclaration",
+                          "start":50,"end":57,"loc":{"start":{"line":2,"column":27},"end":{"line":2,"column":34}},
+                          "declarations": [
+                            {
+                              "type": "VariableDeclarator",
+                              "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34}},
+                              "id": {
+                                "type": "Identifier",
+                                "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"e"},
+                                "name": "e"
+                              },
+                              "init": null
+                            }
+                          ],
+                          "kind": "const"
+                        },
+                        "right": {
+                          "type": "TopicReference",
+                          "start":61,"end":63,"loc":{"start":{"line":2,"column":38},"end":{"line":2,"column":40}}
+                        },
+                        "body": {
+                          "type": "ExpressionStatement",
+                          "start":65,"end":67,"loc":{"start":{"line":2,"column":42},"end":{"line":2,"column":44}},
+                          "expression": {
+                            "type": "Identifier",
+                            "start":65,"end":66,"loc":{"start":{"line":2,"column":42},"end":{"line":2,"column":43},"identifierName":"e"},
+                            "name": "e"
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..713a2f9da3a3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/input.js
@@ -0,0 +1,3 @@
+async function af () {
+  value |> do { for await (const e of sequence) ^^; }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..ab375cbf19e6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    "doExpressions",
+    "asyncGenerators"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..fddba25fc5fe
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-body/output.json
@@ -0,0 +1,93 @@
+{
+  "type": "File",
+  "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":78,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17},"identifierName":"af"},
+          "name": "af"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":21,"end":78,"loc":{"start":{"line":1,"column":21},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":25,"end":76,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":53}},
+              "expression": {
+                "type": "BinaryExpression",
+                "start":25,"end":76,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":53}},
+                "left": {
+                  "type": "Identifier",
+                  "start":25,"end":30,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":7},"identifierName":"value"},
+                  "name": "value"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "DoExpression",
+                  "start":34,"end":76,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":53}},
+                  "async": false,
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":76,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":53}},
+                    "body": [
+                      {
+                        "type": "ForOfStatement",
+                        "start":39,"end":74,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":51}},
+                        "await": true,
+                        "left": {
+                          "type": "VariableDeclaration",
+                          "start":50,"end":57,"loc":{"start":{"line":2,"column":27},"end":{"line":2,"column":34}},
+                          "declarations": [
+                            {
+                              "type": "VariableDeclarator",
+                              "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34}},
+                              "id": {
+                                "type": "Identifier",
+                                "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"e"},
+                                "name": "e"
+                              },
+                              "init": null
+                            }
+                          ],
+                          "kind": "const"
+                        },
+                        "right": {
+                          "type": "Identifier",
+                          "start":61,"end":69,"loc":{"start":{"line":2,"column":38},"end":{"line":2,"column":46},"identifierName":"sequence"},
+                          "name": "sequence"
+                        },
+                        "body": {
+                          "type": "ExpressionStatement",
+                          "start":71,"end":74,"loc":{"start":{"line":2,"column":48},"end":{"line":2,"column":51}},
+                          "expression": {
+                            "type": "TopicReference",
+                            "start":71,"end":73,"loc":{"start":{"line":2,"column":48},"end":{"line":2,"column":50}}
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..132c5f9c1644
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/input.js
@@ -0,0 +1,3 @@
+async function af () {
+  value |> do { for await (const e of ^^) e; }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..ab375cbf19e6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    "doExpressions",
+    "asyncGenerators"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..4f5624112439
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-await-of-loop-transform-and-topic-in-loop-head/output.json
@@ -0,0 +1,93 @@
+{
+  "type": "File",
+  "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":71,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17},"identifierName":"af"},
+          "name": "af"
+        },
+        "generator": false,
+        "async": true,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":21,"end":71,"loc":{"start":{"line":1,"column":21},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":25,"end":69,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":46}},
+              "expression": {
+                "type": "BinaryExpression",
+                "start":25,"end":69,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":46}},
+                "left": {
+                  "type": "Identifier",
+                  "start":25,"end":30,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":7},"identifierName":"value"},
+                  "name": "value"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "DoExpression",
+                  "start":34,"end":69,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":46}},
+                  "async": false,
+                  "body": {
+                    "type": "BlockStatement",
+                    "start":37,"end":69,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":46}},
+                    "body": [
+                      {
+                        "type": "ForOfStatement",
+                        "start":39,"end":67,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":44}},
+                        "await": true,
+                        "left": {
+                          "type": "VariableDeclaration",
+                          "start":50,"end":57,"loc":{"start":{"line":2,"column":27},"end":{"line":2,"column":34}},
+                          "declarations": [
+                            {
+                              "type": "VariableDeclarator",
+                              "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34}},
+                              "id": {
+                                "type": "Identifier",
+                                "start":56,"end":57,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"e"},
+                                "name": "e"
+                              },
+                              "init": null
+                            }
+                          ],
+                          "kind": "const"
+                        },
+                        "right": {
+                          "type": "TopicReference",
+                          "start":61,"end":63,"loc":{"start":{"line":2,"column":38},"end":{"line":2,"column":40}}
+                        },
+                        "body": {
+                          "type": "ExpressionStatement",
+                          "start":65,"end":67,"loc":{"start":{"line":2,"column":42},"end":{"line":2,"column":44}},
+                          "expression": {
+                            "type": "Identifier",
+                            "start":65,"end":66,"loc":{"start":{"line":2,"column":42},"end":{"line":2,"column":43},"identifierName":"e"},
+                            "name": "e"
+                          }
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..35943c02ee31
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { for (let i = 0; i < n; i += 1) ^^; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..de572e961fe4
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,110 @@
+{
+  "type": "File",
+  "start":0,"end":50,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":50}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":50,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":50}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":50,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":50}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":50,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":50}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":50,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":50}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":50,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":50}},
+              "body": [
+                {
+                  "type": "ForStatement",
+                  "start":14,"end":48,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":48}},
+                  "init": {
+                    "type": "VariableDeclaration",
+                    "start":19,"end":28,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":28}},
+                    "declarations": [
+                      {
+                        "type": "VariableDeclarator",
+                        "start":23,"end":28,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":28}},
+                        "id": {
+                          "type": "Identifier",
+                          "start":23,"end":24,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":24},"identifierName":"i"},
+                          "name": "i"
+                        },
+                        "init": {
+                          "type": "NumericLiteral",
+                          "start":27,"end":28,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":28}},
+                          "extra": {
+                            "rawValue": 0,
+                            "raw": "0"
+                          },
+                          "value": 0
+                        }
+                      }
+                    ],
+                    "kind": "let"
+                  },
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":30,"end":35,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":35}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":30,"end":31,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":31},"identifierName":"i"},
+                      "name": "i"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "Identifier",
+                      "start":34,"end":35,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":35},"identifierName":"n"},
+                      "name": "n"
+                    }
+                  },
+                  "update": {
+                    "type": "AssignmentExpression",
+                    "start":37,"end":43,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":43}},
+                    "operator": "+=",
+                    "left": {
+                      "type": "Identifier",
+                      "start":37,"end":38,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":38},"identifierName":"i"},
+                      "name": "i"
+                    },
+                    "right": {
+                      "type": "NumericLiteral",
+                      "start":42,"end":43,"loc":{"start":{"line":1,"column":42},"end":{"line":1,"column":43}},
+                      "extra": {
+                        "rawValue": 1,
+                        "raw": "1"
+                      },
+                      "value": 1
+                    }
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":45,"end":48,"loc":{"start":{"line":1,"column":45},"end":{"line":1,"column":48}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":45,"end":47,"loc":{"start":{"line":1,"column":45},"end":{"line":1,"column":47}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..a115a3f2e5b0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { for (let i = ^^; predicate(i, ^^); i += ^^) i; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..3afffc17b927
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-classic-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,106 @@
+{
+  "type": "File",
+  "start":0,"end":62,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":62}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":62,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":62}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":62,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":62}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":62,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":62}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":62,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":62}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":62,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":62}},
+              "body": [
+                {
+                  "type": "ForStatement",
+                  "start":14,"end":60,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":60}},
+                  "init": {
+                    "type": "VariableDeclaration",
+                    "start":19,"end":29,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":29}},
+                    "declarations": [
+                      {
+                        "type": "VariableDeclarator",
+                        "start":23,"end":29,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":29}},
+                        "id": {
+                          "type": "Identifier",
+                          "start":23,"end":24,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":24},"identifierName":"i"},
+                          "name": "i"
+                        },
+                        "init": {
+                          "type": "TopicReference",
+                          "start":27,"end":29,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":29}}
+                        }
+                      }
+                    ],
+                    "kind": "let"
+                  },
+                  "test": {
+                    "type": "CallExpression",
+                    "start":31,"end":47,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":47}},
+                    "callee": {
+                      "type": "Identifier",
+                      "start":31,"end":40,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":40},"identifierName":"predicate"},
+                      "name": "predicate"
+                    },
+                    "arguments": [
+                      {
+                        "type": "Identifier",
+                        "start":41,"end":42,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":42},"identifierName":"i"},
+                        "name": "i"
+                      },
+                      {
+                        "type": "TopicReference",
+                        "start":44,"end":46,"loc":{"start":{"line":1,"column":44},"end":{"line":1,"column":46}}
+                      }
+                    ]
+                  },
+                  "update": {
+                    "type": "AssignmentExpression",
+                    "start":49,"end":56,"loc":{"start":{"line":1,"column":49},"end":{"line":1,"column":56}},
+                    "operator": "+=",
+                    "left": {
+                      "type": "Identifier",
+                      "start":49,"end":50,"loc":{"start":{"line":1,"column":49},"end":{"line":1,"column":50},"identifierName":"i"},
+                      "name": "i"
+                    },
+                    "right": {
+                      "type": "TopicReference",
+                      "start":54,"end":56,"loc":{"start":{"line":1,"column":54},"end":{"line":1,"column":56}}
+                    }
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":58,"end":60,"loc":{"start":{"line":1,"column":58},"end":{"line":1,"column":60}},
+                    "expression": {
+                      "type": "Identifier",
+                      "start":58,"end":59,"loc":{"start":{"line":1,"column":58},"end":{"line":1,"column":59},"identifierName":"i"},
+                      "name": "i"
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..31ef18436069
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { for (e in object) ^^; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..daa667eaaed9
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,61 @@
+{
+  "type": "File",
+  "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":37}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":37}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":37}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":37,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":37}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":37,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":37}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":37,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":37}},
+              "body": [
+                {
+                  "type": "ForInStatement",
+                  "start":14,"end":35,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":35}},
+                  "left": {
+                    "type": "Identifier",
+                    "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"e"},
+                    "name": "e"
+                  },
+                  "right": {
+                    "type": "Identifier",
+                    "start":24,"end":30,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":30},"identifierName":"object"},
+                    "name": "object"
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":32,"end":35,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":35}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":32,"end":34,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":34}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..fbfcb2157610
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { for (e in ^^) e; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..f230de3579f5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-in-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,61 @@
+{
+  "type": "File",
+  "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":32,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":32}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":32,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":32}},
+              "body": [
+                {
+                  "type": "ForInStatement",
+                  "start":14,"end":30,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":30}},
+                  "left": {
+                    "type": "Identifier",
+                    "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"e"},
+                    "name": "e"
+                  },
+                  "right": {
+                    "type": "TopicReference",
+                    "start":24,"end":26,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":26}}
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":28,"end":30,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":30}},
+                    "expression": {
+                      "type": "Identifier",
+                      "start":28,"end":29,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":29},"identifierName":"e"},
+                      "name": "e"
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..23642b59994e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { for (e of sequence) ^^; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..45b65d93e930
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-body/output.json
@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":39,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":39}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":39,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":39}},
+              "body": [
+                {
+                  "type": "ForOfStatement",
+                  "start":14,"end":37,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":37}},
+                  "await": false,
+                  "left": {
+                    "type": "Identifier",
+                    "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"e"},
+                    "name": "e"
+                  },
+                  "right": {
+                    "type": "Identifier",
+                    "start":24,"end":32,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":32},"identifierName":"sequence"},
+                    "name": "sequence"
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":34,"end":37,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":37}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":34,"end":36,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":36}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..b1eaa87e4c36
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { for (e of ^^) e; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..0a487cc24354
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-for-of-loop-and-topic-in-loop-head/output.json
@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":32,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":32}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":32,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":32}},
+              "body": [
+                {
+                  "type": "ForOfStatement",
+                  "start":14,"end":30,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":30}},
+                  "await": false,
+                  "left": {
+                    "type": "Identifier",
+                    "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"e"},
+                    "name": "e"
+                  },
+                  "right": {
+                    "type": "TopicReference",
+                    "start":24,"end":26,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":26}}
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":28,"end":30,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":30}},
+                    "expression": {
+                      "type": "Identifier",
+                      "start":28,"end":29,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":29},"identifierName":"e"},
+                      "name": "e"
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-body/input.js
new file mode 100644
index 000000000000..4aea463b8e0a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-body/input.js
@@ -0,0 +1 @@
+value |> do { if (yes) null; else if (no) ^^; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-body/output.json
new file mode 100644
index 000000000000..be79908de4c8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-body/output.json
@@ -0,0 +1,74 @@
+{
+  "type": "File",
+  "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":47}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":47}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":47}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":47}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":47,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":47}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":47,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":47}},
+              "body": [
+                {
+                  "type": "IfStatement",
+                  "start":14,"end":45,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":45}},
+                  "test": {
+                    "type": "Identifier",
+                    "start":18,"end":21,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":21},"identifierName":"yes"},
+                    "name": "yes"
+                  },
+                  "consequent": {
+                    "type": "ExpressionStatement",
+                    "start":23,"end":28,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":28}},
+                    "expression": {
+                      "type": "NullLiteral",
+                      "start":23,"end":27,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":27}}
+                    }
+                  },
+                  "alternate": {
+                    "type": "IfStatement",
+                    "start":34,"end":45,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":45}},
+                    "test": {
+                      "type": "Identifier",
+                      "start":38,"end":40,"loc":{"start":{"line":1,"column":38},"end":{"line":1,"column":40},"identifierName":"no"},
+                      "name": "no"
+                    },
+                    "consequent": {
+                      "type": "ExpressionStatement",
+                      "start":42,"end":45,"loc":{"start":{"line":1,"column":42},"end":{"line":1,"column":45}},
+                      "expression": {
+                        "type": "TopicReference",
+                        "start":42,"end":44,"loc":{"start":{"line":1,"column":42},"end":{"line":1,"column":44}}
+                      }
+                    },
+                    "alternate": null
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-if-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-if-body/input.js
new file mode 100644
index 000000000000..1019b6f7d9e0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-if-body/input.js
@@ -0,0 +1 @@
+value |> do { if (yes) null; else ^^; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-if-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-if-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-if-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-if-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-if-body/output.json
new file mode 100644
index 000000000000..dc4340eba991
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-else-if-body/output.json
@@ -0,0 +1,64 @@
+{
+  "type": "File",
+  "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":39,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":39}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":39,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":39}},
+              "body": [
+                {
+                  "type": "IfStatement",
+                  "start":14,"end":37,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":37}},
+                  "test": {
+                    "type": "Identifier",
+                    "start":18,"end":21,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":21},"identifierName":"yes"},
+                    "name": "yes"
+                  },
+                  "consequent": {
+                    "type": "ExpressionStatement",
+                    "start":23,"end":28,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":28}},
+                    "expression": {
+                      "type": "NullLiteral",
+                      "start":23,"end":27,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":27}}
+                    }
+                  },
+                  "alternate": {
+                    "type": "ExpressionStatement",
+                    "start":34,"end":37,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":37}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":34,"end":36,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":36}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-body/input.js
new file mode 100644
index 000000000000..d1305366931e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-body/input.js
@@ -0,0 +1 @@
+value |> do { if (yes) ^^; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-body/output.json
new file mode 100644
index 000000000000..e16a87fba31f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-body/output.json
@@ -0,0 +1,57 @@
+{
+  "type": "File",
+  "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":28,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":28}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":28,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":28}},
+              "body": [
+                {
+                  "type": "IfStatement",
+                  "start":14,"end":26,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":26}},
+                  "test": {
+                    "type": "Identifier",
+                    "start":18,"end":21,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":21},"identifierName":"yes"},
+                    "name": "yes"
+                  },
+                  "consequent": {
+                    "type": "ExpressionStatement",
+                    "start":23,"end":26,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":26}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":23,"end":25,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":25}}
+                    }
+                  },
+                  "alternate": null
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-head/input.js
new file mode 100644
index 000000000000..d1caca34d0cf
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-head/input.js
@@ -0,0 +1 @@
+value |> do { if (^^) 1; else 0; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-head/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-head/output.json
new file mode 100644
index 000000000000..727a3813b9f7
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-if-statement-and-topic-in-if-head/output.json
@@ -0,0 +1,73 @@
+{
+  "type": "File",
+  "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":34}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":34}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":34}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":34}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":34,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":34}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":34,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":34}},
+              "body": [
+                {
+                  "type": "IfStatement",
+                  "start":14,"end":32,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":32}},
+                  "test": {
+                    "type": "TopicReference",
+                    "start":18,"end":20,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":20}}
+                  },
+                  "consequent": {
+                    "type": "ExpressionStatement",
+                    "start":22,"end":24,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":24}},
+                    "expression": {
+                      "type": "NumericLiteral",
+                      "start":22,"end":23,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":23}},
+                      "extra": {
+                        "rawValue": 1,
+                        "raw": "1"
+                      },
+                      "value": 1
+                    }
+                  },
+                  "alternate": {
+                    "type": "ExpressionStatement",
+                    "start":30,"end":32,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":32}},
+                    "expression": {
+                      "type": "NumericLiteral",
+                      "start":30,"end":31,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":31}},
+                      "extra": {
+                        "rawValue": 0,
+                        "raw": "0"
+                      },
+                      "value": 0
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-body/input.js
new file mode 100644
index 000000000000..c7309bf7f69c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-body/input.js
@@ -0,0 +1,7 @@
+value |> do {
+  switch (number) {
+    case 0: ^^;
+    case 1: ^^ + 1;
+    default: ^^ + 10;
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-body/output.json
new file mode 100644
index 000000000000..3fa9c9962c8b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-body/output.json
@@ -0,0 +1,139 @@
+{
+  "type": "File",
+  "start":0,"end":97,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":97,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":97,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":97,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":97,"loc":{"start":{"line":1,"column":9},"end":{"line":7,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":97,"loc":{"start":{"line":1,"column":12},"end":{"line":7,"column":1}},
+              "body": [
+                {
+                  "type": "SwitchStatement",
+                  "start":16,"end":95,"loc":{"start":{"line":2,"column":2},"end":{"line":6,"column":3}},
+                  "discriminant": {
+                    "type": "Identifier",
+                    "start":24,"end":30,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":16},"identifierName":"number"},
+                    "name": "number"
+                  },
+                  "cases": [
+                    {
+                      "type": "SwitchCase",
+                      "start":38,"end":49,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":15}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":46,"end":49,"loc":{"start":{"line":3,"column":12},"end":{"line":3,"column":15}},
+                          "expression": {
+                            "type": "TopicReference",
+                            "start":46,"end":48,"loc":{"start":{"line":3,"column":12},"end":{"line":3,"column":14}}
+                          }
+                        }
+                      ],
+                      "test": {
+                        "type": "NumericLiteral",
+                        "start":43,"end":44,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":10}},
+                        "extra": {
+                          "rawValue": 0,
+                          "raw": "0"
+                        },
+                        "value": 0
+                      }
+                    },
+                    {
+                      "type": "SwitchCase",
+                      "start":54,"end":69,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":19}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":62,"end":69,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":19}},
+                          "expression": {
+                            "type": "BinaryExpression",
+                            "start":62,"end":68,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":18}},
+                            "left": {
+                              "type": "TopicReference",
+                              "start":62,"end":64,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":14}}
+                            },
+                            "operator": "+",
+                            "right": {
+                              "type": "NumericLiteral",
+                              "start":67,"end":68,"loc":{"start":{"line":4,"column":17},"end":{"line":4,"column":18}},
+                              "extra": {
+                                "rawValue": 1,
+                                "raw": "1"
+                              },
+                              "value": 1
+                            }
+                          }
+                        }
+                      ],
+                      "test": {
+                        "type": "NumericLiteral",
+                        "start":59,"end":60,"loc":{"start":{"line":4,"column":9},"end":{"line":4,"column":10}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    },
+                    {
+                      "type": "SwitchCase",
+                      "start":74,"end":91,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":21}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":83,"end":91,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":21}},
+                          "expression": {
+                            "type": "BinaryExpression",
+                            "start":83,"end":90,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":20}},
+                            "left": {
+                              "type": "TopicReference",
+                              "start":83,"end":85,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":15}}
+                            },
+                            "operator": "+",
+                            "right": {
+                              "type": "NumericLiteral",
+                              "start":88,"end":90,"loc":{"start":{"line":5,"column":18},"end":{"line":5,"column":20}},
+                              "extra": {
+                                "rawValue": 10,
+                                "raw": "10"
+                              },
+                              "value": 10
+                            }
+                          }
+                        }
+                      ],
+                      "test": null
+                    }
+                  ]
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-head/input.js
new file mode 100644
index 000000000000..0fa54d2628f1
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-head/input.js
@@ -0,0 +1,7 @@
+value |> do {
+  switch (^^) {
+    case 0: 50;
+    case 1: 60;
+    default: 70;
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-head/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-head/output.json
new file mode 100644
index 000000000000..93929e99ee58
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-switch-statement-and-topic-in-switch-head/output.json
@@ -0,0 +1,125 @@
+{
+  "type": "File",
+  "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":84,"loc":{"start":{"line":1,"column":9},"end":{"line":7,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":84,"loc":{"start":{"line":1,"column":12},"end":{"line":7,"column":1}},
+              "body": [
+                {
+                  "type": "SwitchStatement",
+                  "start":16,"end":82,"loc":{"start":{"line":2,"column":2},"end":{"line":6,"column":3}},
+                  "discriminant": {
+                    "type": "TopicReference",
+                    "start":24,"end":26,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":12}}
+                  },
+                  "cases": [
+                    {
+                      "type": "SwitchCase",
+                      "start":34,"end":45,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":15}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":42,"end":45,"loc":{"start":{"line":3,"column":12},"end":{"line":3,"column":15}},
+                          "expression": {
+                            "type": "NumericLiteral",
+                            "start":42,"end":44,"loc":{"start":{"line":3,"column":12},"end":{"line":3,"column":14}},
+                            "extra": {
+                              "rawValue": 50,
+                              "raw": "50"
+                            },
+                            "value": 50
+                          }
+                        }
+                      ],
+                      "test": {
+                        "type": "NumericLiteral",
+                        "start":39,"end":40,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":10}},
+                        "extra": {
+                          "rawValue": 0,
+                          "raw": "0"
+                        },
+                        "value": 0
+                      }
+                    },
+                    {
+                      "type": "SwitchCase",
+                      "start":50,"end":61,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":15}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":58,"end":61,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":15}},
+                          "expression": {
+                            "type": "NumericLiteral",
+                            "start":58,"end":60,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":14}},
+                            "extra": {
+                              "rawValue": 60,
+                              "raw": "60"
+                            },
+                            "value": 60
+                          }
+                        }
+                      ],
+                      "test": {
+                        "type": "NumericLiteral",
+                        "start":55,"end":56,"loc":{"start":{"line":4,"column":9},"end":{"line":4,"column":10}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    },
+                    {
+                      "type": "SwitchCase",
+                      "start":66,"end":78,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":16}},
+                      "consequent": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":75,"end":78,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":16}},
+                          "expression": {
+                            "type": "NumericLiteral",
+                            "start":75,"end":77,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":15}},
+                            "extra": {
+                              "rawValue": 70,
+                              "raw": "70"
+                            },
+                            "value": 70
+                          }
+                        }
+                      ],
+                      "test": null
+                    }
+                  ]
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-topic-identity/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-topic-identity/input.js
new file mode 100644
index 000000000000..0bda1af6aee9
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-topic-identity/input.js
@@ -0,0 +1 @@
+value |> do { ^^; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-topic-identity/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-topic-identity/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-topic-identity/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-topic-identity/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-topic-identity/output.json
new file mode 100644
index 000000000000..2c53651ce7fe
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-topic-identity/output.json
@@ -0,0 +1,47 @@
+{
+  "type": "File",
+  "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":19,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":19}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":19,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":19}},
+              "body": [
+                {
+                  "type": "ExpressionStatement",
+                  "start":14,"end":17,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":17}},
+                  "expression": {
+                    "type": "TopicReference",
+                    "start":14,"end":16,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":16}}
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/input.js
new file mode 100644
index 000000000000..bd46d35dd51a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/input.js
@@ -0,0 +1,4 @@
+value |> do {
+  try { JSON.parse(^^); }
+  catch (error) { console.error(^^); }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/output.json
new file mode 100644
index 000000000000..eae50a367908
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-catch-clause/output.json
@@ -0,0 +1,125 @@
+{
+  "type": "File",
+  "start":0,"end":80,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":80,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":80,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":80,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":80,"loc":{"start":{"line":1,"column":9},"end":{"line":4,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":80,"loc":{"start":{"line":1,"column":12},"end":{"line":4,"column":1}},
+              "body": [
+                {
+                  "type": "TryStatement",
+                  "start":16,"end":78,"loc":{"start":{"line":2,"column":2},"end":{"line":3,"column":38}},
+                  "block": {
+                    "type": "BlockStatement",
+                    "start":20,"end":39,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":25}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":22,"end":37,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":23}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":22,"end":36,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":22}},
+                          "callee": {
+                            "type": "MemberExpression",
+                            "start":22,"end":32,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":18}},
+                            "object": {
+                              "type": "Identifier",
+                              "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
+                              "name": "JSON"
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
+                              "name": "parse"
+                            }
+                          },
+                          "arguments": [
+                            {
+                              "type": "TopicReference",
+                              "start":33,"end":35,"loc":{"start":{"line":2,"column":19},"end":{"line":2,"column":21}}
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  },
+                  "handler": {
+                    "type": "CatchClause",
+                    "start":42,"end":78,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":38}},
+                    "param": {
+                      "type": "Identifier",
+                      "start":49,"end":54,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":14},"identifierName":"error"},
+                      "name": "error"
+                    },
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":56,"end":78,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":38}},
+                      "body": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":58,"end":76,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":36}},
+                          "expression": {
+                            "type": "CallExpression",
+                            "start":58,"end":75,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":35}},
+                            "callee": {
+                              "type": "MemberExpression",
+                              "start":58,"end":71,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":31}},
+                              "object": {
+                                "type": "Identifier",
+                                "start":58,"end":65,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
+                                "name": "console"
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "Identifier",
+                                "start":66,"end":71,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            },
+                            "arguments": [
+                              {
+                                "type": "TopicReference",
+                                "start":72,"end":74,"loc":{"start":{"line":3,"column":32},"end":{"line":3,"column":34}}
+                              }
+                            ]
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  },
+                  "finalizer": null
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/input.js
new file mode 100644
index 000000000000..ac5a8f522f39
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/input.js
@@ -0,0 +1,5 @@
+value |> do {
+  try { JSON.parse(whatever); }
+  catch (error) { console.error(error); }
+  finally { something(^^); }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/output.json
new file mode 100644
index 000000000000..798e55fdc030
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-finally-clause/output.json
@@ -0,0 +1,152 @@
+{
+  "type": "File",
+  "start":0,"end":118,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":118,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":118,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":118,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":118,"loc":{"start":{"line":1,"column":9},"end":{"line":5,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":118,"loc":{"start":{"line":1,"column":12},"end":{"line":5,"column":1}},
+              "body": [
+                {
+                  "type": "TryStatement",
+                  "start":16,"end":116,"loc":{"start":{"line":2,"column":2},"end":{"line":4,"column":28}},
+                  "block": {
+                    "type": "BlockStatement",
+                    "start":20,"end":45,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":31}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":22,"end":43,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":29}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":22,"end":42,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":28}},
+                          "callee": {
+                            "type": "MemberExpression",
+                            "start":22,"end":32,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":18}},
+                            "object": {
+                              "type": "Identifier",
+                              "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
+                              "name": "JSON"
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
+                              "name": "parse"
+                            }
+                          },
+                          "arguments": [
+                            {
+                              "type": "Identifier",
+                              "start":33,"end":41,"loc":{"start":{"line":2,"column":19},"end":{"line":2,"column":27},"identifierName":"whatever"},
+                              "name": "whatever"
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  },
+                  "handler": {
+                    "type": "CatchClause",
+                    "start":48,"end":87,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":41}},
+                    "param": {
+                      "type": "Identifier",
+                      "start":55,"end":60,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":14},"identifierName":"error"},
+                      "name": "error"
+                    },
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":62,"end":87,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":41}},
+                      "body": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":64,"end":85,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":39}},
+                          "expression": {
+                            "type": "CallExpression",
+                            "start":64,"end":84,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":38}},
+                            "callee": {
+                              "type": "MemberExpression",
+                              "start":64,"end":77,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":31}},
+                              "object": {
+                                "type": "Identifier",
+                                "start":64,"end":71,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
+                                "name": "console"
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "Identifier",
+                                "start":72,"end":77,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            },
+                            "arguments": [
+                              {
+                                "type": "Identifier",
+                                "start":78,"end":83,"loc":{"start":{"line":3,"column":32},"end":{"line":3,"column":37},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            ]
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  },
+                  "finalizer": {
+                    "type": "BlockStatement",
+                    "start":98,"end":116,"loc":{"start":{"line":4,"column":10},"end":{"line":4,"column":28}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":100,"end":114,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":26}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":100,"end":113,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":25}},
+                          "callee": {
+                            "type": "Identifier",
+                            "start":100,"end":109,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":21},"identifierName":"something"},
+                            "name": "something"
+                          },
+                          "arguments": [
+                            {
+                              "type": "TopicReference",
+                              "start":110,"end":112,"loc":{"start":{"line":4,"column":22},"end":{"line":4,"column":24}}
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/input.js
new file mode 100644
index 000000000000..d104b53442b0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/input.js
@@ -0,0 +1,5 @@
+value |> do {
+  try { JSON.parse(^^); }
+  catch (error) { console.error(error); }
+  finally { something(); }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/output.json
new file mode 100644
index 000000000000..963ec3e5f04b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-finally-statements-and-topic-in-try-clause/output.json
@@ -0,0 +1,146 @@
+{
+  "type": "File",
+  "start":0,"end":110,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":110,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":110,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":110,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":110,"loc":{"start":{"line":1,"column":9},"end":{"line":5,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":110,"loc":{"start":{"line":1,"column":12},"end":{"line":5,"column":1}},
+              "body": [
+                {
+                  "type": "TryStatement",
+                  "start":16,"end":108,"loc":{"start":{"line":2,"column":2},"end":{"line":4,"column":26}},
+                  "block": {
+                    "type": "BlockStatement",
+                    "start":20,"end":39,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":25}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":22,"end":37,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":23}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":22,"end":36,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":22}},
+                          "callee": {
+                            "type": "MemberExpression",
+                            "start":22,"end":32,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":18}},
+                            "object": {
+                              "type": "Identifier",
+                              "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
+                              "name": "JSON"
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
+                              "name": "parse"
+                            }
+                          },
+                          "arguments": [
+                            {
+                              "type": "TopicReference",
+                              "start":33,"end":35,"loc":{"start":{"line":2,"column":19},"end":{"line":2,"column":21}}
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  },
+                  "handler": {
+                    "type": "CatchClause",
+                    "start":42,"end":81,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":41}},
+                    "param": {
+                      "type": "Identifier",
+                      "start":49,"end":54,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":14},"identifierName":"error"},
+                      "name": "error"
+                    },
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":56,"end":81,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":41}},
+                      "body": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":58,"end":79,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":39}},
+                          "expression": {
+                            "type": "CallExpression",
+                            "start":58,"end":78,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":38}},
+                            "callee": {
+                              "type": "MemberExpression",
+                              "start":58,"end":71,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":31}},
+                              "object": {
+                                "type": "Identifier",
+                                "start":58,"end":65,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
+                                "name": "console"
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "Identifier",
+                                "start":66,"end":71,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            },
+                            "arguments": [
+                              {
+                                "type": "Identifier",
+                                "start":72,"end":77,"loc":{"start":{"line":3,"column":32},"end":{"line":3,"column":37},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            ]
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  },
+                  "finalizer": {
+                    "type": "BlockStatement",
+                    "start":92,"end":108,"loc":{"start":{"line":4,"column":10},"end":{"line":4,"column":26}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":94,"end":106,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":24}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":94,"end":105,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":23}},
+                          "callee": {
+                            "type": "Identifier",
+                            "start":94,"end":103,"loc":{"start":{"line":4,"column":12},"end":{"line":4,"column":21},"identifierName":"something"},
+                            "name": "something"
+                          },
+                          "arguments": []
+                        }
+                      }
+                    ],
+                    "directives": []
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-statements-topic-in-try-clause/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-statements-topic-in-try-clause/input.js
new file mode 100644
index 000000000000..b1571556cb70
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-statements-topic-in-try-clause/input.js
@@ -0,0 +1,4 @@
+value |> do {
+  try { JSON.parse(^^); }
+  catch (error) { console.error(error); }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-statements-topic-in-try-clause/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-statements-topic-in-try-clause/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-statements-topic-in-try-clause/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-statements-topic-in-try-clause/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-statements-topic-in-try-clause/output.json
new file mode 100644
index 000000000000..11241eb3ca0e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-try-catch-statements-topic-in-try-clause/output.json
@@ -0,0 +1,126 @@
+{
+  "type": "File",
+  "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":83,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":83,"loc":{"start":{"line":1,"column":9},"end":{"line":4,"column":1}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":83,"loc":{"start":{"line":1,"column":12},"end":{"line":4,"column":1}},
+              "body": [
+                {
+                  "type": "TryStatement",
+                  "start":16,"end":81,"loc":{"start":{"line":2,"column":2},"end":{"line":3,"column":41}},
+                  "block": {
+                    "type": "BlockStatement",
+                    "start":20,"end":39,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":25}},
+                    "body": [
+                      {
+                        "type": "ExpressionStatement",
+                        "start":22,"end":37,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":23}},
+                        "expression": {
+                          "type": "CallExpression",
+                          "start":22,"end":36,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":22}},
+                          "callee": {
+                            "type": "MemberExpression",
+                            "start":22,"end":32,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":18}},
+                            "object": {
+                              "type": "Identifier",
+                              "start":22,"end":26,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12},"identifierName":"JSON"},
+                              "name": "JSON"
+                            },
+                            "computed": false,
+                            "property": {
+                              "type": "Identifier",
+                              "start":27,"end":32,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":18},"identifierName":"parse"},
+                              "name": "parse"
+                            }
+                          },
+                          "arguments": [
+                            {
+                              "type": "TopicReference",
+                              "start":33,"end":35,"loc":{"start":{"line":2,"column":19},"end":{"line":2,"column":21}}
+                            }
+                          ]
+                        }
+                      }
+                    ],
+                    "directives": []
+                  },
+                  "handler": {
+                    "type": "CatchClause",
+                    "start":42,"end":81,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":41}},
+                    "param": {
+                      "type": "Identifier",
+                      "start":49,"end":54,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":14},"identifierName":"error"},
+                      "name": "error"
+                    },
+                    "body": {
+                      "type": "BlockStatement",
+                      "start":56,"end":81,"loc":{"start":{"line":3,"column":16},"end":{"line":3,"column":41}},
+                      "body": [
+                        {
+                          "type": "ExpressionStatement",
+                          "start":58,"end":79,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":39}},
+                          "expression": {
+                            "type": "CallExpression",
+                            "start":58,"end":78,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":38}},
+                            "callee": {
+                              "type": "MemberExpression",
+                              "start":58,"end":71,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":31}},
+                              "object": {
+                                "type": "Identifier",
+                                "start":58,"end":65,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":25},"identifierName":"console"},
+                                "name": "console"
+                              },
+                              "computed": false,
+                              "property": {
+                                "type": "Identifier",
+                                "start":66,"end":71,"loc":{"start":{"line":3,"column":26},"end":{"line":3,"column":31},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            },
+                            "arguments": [
+                              {
+                                "type": "Identifier",
+                                "start":72,"end":77,"loc":{"start":{"line":3,"column":32},"end":{"line":3,"column":37},"identifierName":"error"},
+                                "name": "error"
+                              }
+                            ]
+                          }
+                        }
+                      ],
+                      "directives": []
+                    }
+                  },
+                  "finalizer": null
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-body/input.js
new file mode 100644
index 000000000000..381952ffe772
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-body/input.js
@@ -0,0 +1 @@
+value |> do { while (x < 50) x += ^^; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-body/output.json
new file mode 100644
index 000000000000..ac3f99102fec
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-body/output.json
@@ -0,0 +1,80 @@
+{
+  "type": "File",
+  "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":39,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":39}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":39,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":39}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":39,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":39}},
+              "body": [
+                {
+                  "type": "WhileStatement",
+                  "start":14,"end":37,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":37}},
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":21,"end":27,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":27}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":21,"end":22,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":22},"identifierName":"x"},
+                      "name": "x"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "NumericLiteral",
+                      "start":25,"end":27,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":27}},
+                      "extra": {
+                        "rawValue": 50,
+                        "raw": "50"
+                      },
+                      "value": 50
+                    }
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":29,"end":37,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":37}},
+                    "expression": {
+                      "type": "AssignmentExpression",
+                      "start":29,"end":36,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":36}},
+                      "operator": "+=",
+                      "left": {
+                        "type": "Identifier",
+                        "start":29,"end":30,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":30},"identifierName":"x"},
+                        "name": "x"
+                      },
+                      "right": {
+                        "type": "TopicReference",
+                        "start":34,"end":36,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":36}}
+                      }
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-head/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-head/input.js
new file mode 100644
index 000000000000..f26c89059aeb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-head/input.js
@@ -0,0 +1 @@
+value |> do { while (x < ^^) x += 1; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-head/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-head/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-head/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-head/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-head/output.json
new file mode 100644
index 000000000000..0f197cbea8b2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-while-loop-topic-in-loop-head/output.json
@@ -0,0 +1,80 @@
+{
+  "type": "File",
+  "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":38,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":38}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":38,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":38}},
+              "body": [
+                {
+                  "type": "WhileStatement",
+                  "start":14,"end":36,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":36}},
+                  "test": {
+                    "type": "BinaryExpression",
+                    "start":21,"end":27,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":27}},
+                    "left": {
+                      "type": "Identifier",
+                      "start":21,"end":22,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":22},"identifierName":"x"},
+                      "name": "x"
+                    },
+                    "operator": "<",
+                    "right": {
+                      "type": "TopicReference",
+                      "start":25,"end":27,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":27}}
+                    }
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":29,"end":36,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":36}},
+                    "expression": {
+                      "type": "AssignmentExpression",
+                      "start":29,"end":35,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":35}},
+                      "operator": "+=",
+                      "left": {
+                        "type": "Identifier",
+                        "start":29,"end":30,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":30},"identifierName":"x"},
+                        "name": "x"
+                      },
+                      "right": {
+                        "type": "NumericLiteral",
+                        "start":34,"end":35,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":35}},
+                        "extra": {
+                          "rawValue": 1,
+                          "raw": "1"
+                        },
+                        "value": 1
+                      }
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-with-block-topic-in-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-with-block-topic-in-body/input.js
new file mode 100644
index 000000000000..c6ab3ba44bb9
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-with-block-topic-in-body/input.js
@@ -0,0 +1 @@
+value |> do { with ({}) ^^; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-with-block-topic-in-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-with-block-topic-in-body/options.json
new file mode 100644
index 000000000000..94dfada55ca3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-with-block-topic-in-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "doExpressions"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-with-block-topic-in-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-with-block-topic-in-body/output.json
new file mode 100644
index 000000000000..4b7b5543bb3b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-do-transform-with-block-topic-in-body/output.json
@@ -0,0 +1,56 @@
+{
+  "type": "File",
+  "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "DoExpression",
+            "start":9,"end":29,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":29}},
+            "async": false,
+            "body": {
+              "type": "BlockStatement",
+              "start":12,"end":29,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":29}},
+              "body": [
+                {
+                  "type": "WithStatement",
+                  "start":14,"end":27,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":27}},
+                  "object": {
+                    "type": "ObjectExpression",
+                    "start":20,"end":22,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":22}},
+                    "properties": []
+                  },
+                  "body": {
+                    "type": "ExpressionStatement",
+                    "start":24,"end":27,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":27}},
+                    "expression": {
+                      "type": "TopicReference",
+                      "start":24,"end":26,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":26}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-loose-with-topic-first-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-loose-with-topic-first-without-spaces/input.js
new file mode 100644
index 000000000000..1bf01584ef25
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-loose-with-topic-first-without-spaces/input.js
@@ -0,0 +1 @@
+value |> ^^==1
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-loose-with-topic-first-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-loose-with-topic-first-without-spaces/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-loose-with-topic-first-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-loose-with-topic-first-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-loose-with-topic-first-without-spaces/output.json
new file mode 100644
index 000000000000..98ecc4bca832
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-loose-with-topic-first-without-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":14,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":14}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "==",
+            "right": {
+              "type": "NumericLiteral",
+              "start":13,"end":14,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":14}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-strict-with-topic-first-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-strict-with-topic-first-without-spaces/input.js
new file mode 100644
index 000000000000..eff56264f60c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-strict-with-topic-first-without-spaces/input.js
@@ -0,0 +1 @@
+value |> ^^===1
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-strict-with-topic-first-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-strict-with-topic-first-without-spaces/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-strict-with-topic-first-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-strict-with-topic-first-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-strict-with-topic-first-without-spaces/output.json
new file mode 100644
index 000000000000..0d9b61f0bf65
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-equality-strict-with-topic-first-without-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "===",
+            "right": {
+              "type": "NumericLiteral",
+              "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15}},
+              "extra": {
+                "rawValue": 1,
+                "raw": "1"
+              },
+              "value": 1
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-with-topic-in-argument/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-with-topic-in-argument/input.js
new file mode 100644
index 000000000000..230a2929ae2b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-with-topic-in-argument/input.js
@@ -0,0 +1 @@
+value |> f(^^)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-with-topic-in-argument/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-with-topic-in-argument/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-with-topic-in-argument/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-with-topic-in-argument/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-with-topic-in-argument/output.json
new file mode 100644
index 000000000000..a2fa21c6ceb7
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-with-topic-in-argument/output.json
@@ -0,0 +1,42 @@
+{
+  "type": "File",
+  "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":14,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":14}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "CallExpression",
+            "start":9,"end":14,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":14}},
+            "callee": {
+              "type": "Identifier",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"f"},
+              "name": "f"
+            },
+            "arguments": [
+              {
+                "type": "TopicReference",
+                "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+              }
+            ]
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-without-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-without-topic/input.js
new file mode 100644
index 000000000000..15a3d7657b9c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-without-topic/input.js
@@ -0,0 +1 @@
+value |> f
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-without-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-without-topic/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-without-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-without-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-without-topic/output.json
new file mode 100644
index 000000000000..3917568d724f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-call-without-topic/output.json
@@ -0,0 +1,35 @@
+{
+  "type": "File",
+  "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "Identifier",
+            "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"f"},
+            "name": "f"
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-another-pipe-in-function-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-another-pipe-in-function-body/input.js
new file mode 100644
index 000000000000..15025273a903
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-another-pipe-in-function-body/input.js
@@ -0,0 +1 @@
+x |> function () { ^^ |> ^^ }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-another-pipe-in-function-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-another-pipe-in-function-body/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-another-pipe-in-function-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-another-pipe-in-function-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-another-pipe-in-function-body/output.json
new file mode 100644
index 000000000000..f81c748e7378
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-another-pipe-in-function-body/output.json
@@ -0,0 +1,59 @@
+{
+  "type": "File",
+  "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":29,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":29}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "FunctionExpression",
+            "start":5,"end":29,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":29}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BlockStatement",
+              "start":17,"end":29,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":29}},
+              "body": [
+                {
+                  "type": "ExpressionStatement",
+                  "start":19,"end":27,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":27}},
+                  "expression": {
+                    "type": "BinaryExpression",
+                    "start":19,"end":27,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":27}},
+                    "left": {
+                      "type": "TopicReference",
+                      "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}}
+                    },
+                    "operator": "|>",
+                    "right": {
+                      "type": "TopicReference",
+                      "start":25,"end":27,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":27}}
+                    }
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-default-parameter/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-default-parameter/input.js
new file mode 100644
index 000000000000..3ff87e96dff6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-default-parameter/input.js
@@ -0,0 +1 @@
+value |> function (x = ^^) { return x; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-default-parameter/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-default-parameter/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-default-parameter/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-default-parameter/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-default-parameter/output.json
new file mode 100644
index 000000000000..640dfd370737
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-default-parameter/output.json
@@ -0,0 +1,65 @@
+{
+  "type": "File",
+  "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":40}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":40}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":40}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":40}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "FunctionExpression",
+            "start":9,"end":40,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":40}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "AssignmentPattern",
+                "start":19,"end":25,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":25}},
+                "left": {
+                  "type": "Identifier",
+                  "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"x"},
+                  "name": "x"
+                },
+                "right": {
+                  "type": "TopicReference",
+                  "start":23,"end":25,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":25}}
+                }
+              }
+            ],
+            "body": {
+              "type": "BlockStatement",
+              "start":27,"end":40,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":40}},
+              "body": [
+                {
+                  "type": "ReturnStatement",
+                  "start":29,"end":38,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":38}},
+                  "argument": {
+                    "type": "Identifier",
+                    "start":36,"end":37,"loc":{"start":{"line":1,"column":36},"end":{"line":1,"column":37},"identifierName":"x"},
+                    "name": "x"
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-function-body/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-function-body/input.js
new file mode 100644
index 000000000000..b27ad6d60dd2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-function-body/input.js
@@ -0,0 +1 @@
+x |> function () { ^^ }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-function-body/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-function-body/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-function-body/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-function-body/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-function-body/output.json
new file mode 100644
index 000000000000..ab81762b5445
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-function-definition-with-topic-in-function-body/output.json
@@ -0,0 +1,50 @@
+{
+  "type": "File",
+  "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "FunctionExpression",
+            "start":5,"end":23,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":23}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BlockStatement",
+              "start":17,"end":23,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":23}},
+              "body": [
+                {
+                  "type": "ExpressionStatement",
+                  "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}},
+                  "expression": {
+                    "type": "TopicReference",
+                    "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}}
+                  }
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-topic/input.js
new file mode 100644
index 000000000000..a18cbd0f1bb2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-topic/input.js
@@ -0,0 +1 @@
+value |> #
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-topic/options.json
new file mode 100644
index 000000000000..332d1bfe8aae
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-topic/options.json
@@ -0,0 +1,4 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]],
+  "throws": "Invalid topic token #. In order to use # as a topic reference, the pipelineOperator plugin must be configured with { \"proposal\": \"hack\", \"topicToken\": \"#\" }. (1:9)"
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-tuple/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-tuple/input.js
new file mode 100644
index 000000000000..5a6ea279ee6f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-tuple/input.js
@@ -0,0 +1,2 @@
+#[0];
+1 |> #[0, ^^];
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-tuple/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-tuple/options.json
new file mode 100644
index 000000000000..16ae6a6075f2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-tuple/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    ["recordAndTuple", { "syntaxType": "hash" }]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-tuple/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-tuple/output.json
new file mode 100644
index 000000000000..4056d03b8c29
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-hash-tuple/output.json
@@ -0,0 +1,69 @@
+{
+  "type": "File",
+  "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":14}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":20,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":14}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5}},
+        "expression": {
+          "type": "TupleExpression",
+          "start":0,"end":4,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":4}},
+          "elements": [
+            {
+              "type": "NumericLiteral",
+              "start":2,"end":3,"loc":{"start":{"line":1,"column":2},"end":{"line":1,"column":3}},
+              "extra": {
+                "rawValue": 0,
+                "raw": "0"
+              },
+              "value": 0
+            }
+          ]
+        }
+      },
+      {
+        "type": "ExpressionStatement",
+        "start":6,"end":20,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":14}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":6,"end":19,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":13}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":6,"end":7,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":1}},
+            "extra": {
+              "rawValue": 1,
+              "raw": "1"
+            },
+            "value": 1
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TupleExpression",
+            "start":11,"end":19,"loc":{"start":{"line":2,"column":5},"end":{"line":2,"column":13}},
+            "elements": [
+              {
+                "type": "NumericLiteral",
+                "start":13,"end":14,"loc":{"start":{"line":2,"column":7},"end":{"line":2,"column":8}},
+                "extra": {
+                  "rawValue": 0,
+                  "raw": "0"
+                },
+                "value": 0
+              },
+              {
+                "type": "TopicReference",
+                "start":16,"end":18,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":12}}
+              }
+            ]
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-mixed-pipeline-plugins/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-mixed-pipeline-plugins/input.js
new file mode 100644
index 000000000000..ebfd2971b61d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-mixed-pipeline-plugins/input.js
@@ -0,0 +1 @@
+value |> ^^
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-mixed-pipeline-plugins/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-mixed-pipeline-plugins/options.json
new file mode 100644
index 000000000000..524e72afed8f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-mixed-pipeline-plugins/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }], "pipelineOperator"]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-mixed-pipeline-plugins/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-mixed-pipeline-plugins/output.json
new file mode 100644
index 000000000000..8b15798610ae
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-mixed-pipeline-plugins/output.json
@@ -0,0 +1,31 @@
+{
+  "type": "File",
+  "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TopicReference",
+            "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-with-required-topics/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-with-required-topics/input.js
new file mode 100644
index 000000000000..13668512bfdd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-with-required-topics/input.js
@@ -0,0 +1 @@
+x |> ($ => ^^ |> f(^^, $) |> ^^ > 1)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-with-required-topics/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-with-required-topics/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-with-required-topics/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-with-required-topics/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-with-required-topics/output.json
new file mode 100644
index 000000000000..c715bce7e7ac
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-with-required-topics/output.json
@@ -0,0 +1,97 @@
+{
+  "type": "File",
+  "start":0,"end":36,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":36}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":36,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":36}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":36,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":36}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":36,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":36}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":6,"end":35,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":35}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"$"},
+                "name": "$"
+              }
+            ],
+            "body": {
+              "type": "BinaryExpression",
+              "start":11,"end":35,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":35}},
+              "left": {
+                "type": "TopicReference",
+                "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+              },
+              "operator": "|>",
+              "right": {
+                "type": "BinaryExpression",
+                "start":17,"end":35,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":35}},
+                "left": {
+                  "type": "CallExpression",
+                  "start":17,"end":25,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":25}},
+                  "callee": {
+                    "type": "Identifier",
+                    "start":17,"end":18,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":18},"identifierName":"f"},
+                    "name": "f"
+                  },
+                  "arguments": [
+                    {
+                      "type": "TopicReference",
+                      "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}}
+                    },
+                    {
+                      "type": "Identifier",
+                      "start":23,"end":24,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":24},"identifierName":"$"},
+                      "name": "$"
+                    }
+                  ]
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "BinaryExpression",
+                  "start":29,"end":35,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":35}},
+                  "left": {
+                    "type": "TopicReference",
+                    "start":29,"end":31,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":31}}
+                  },
+                  "operator": ">",
+                  "right": {
+                    "type": "NumericLiteral",
+                    "start":34,"end":35,"loc":{"start":{"line":1,"column":34},"end":{"line":1,"column":35}},
+                    "extra": {
+                      "rawValue": 1,
+                      "raw": "1"
+                    },
+                    "value": 1
+                  }
+                }
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-inner-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-inner-topic/input.js
new file mode 100644
index 000000000000..772174790e79
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-inner-topic/input.js
@@ -0,0 +1 @@
+x |> ($ => ^^ |> $ + 1)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-inner-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-inner-topic/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-inner-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-inner-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-inner-topic/output.json
new file mode 100644
index 000000000000..d0b6b79bd97e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-inner-topic/output.json
@@ -0,0 +1,76 @@
+{
+  "type": "File",
+  "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:17)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":6,"end":22,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":22}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"$"},
+                "name": "$"
+              }
+            ],
+            "body": {
+              "type": "BinaryExpression",
+              "start":11,"end":22,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":22}},
+              "left": {
+                "type": "TopicReference",
+                "start":11,"end":13,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":13}}
+              },
+              "operator": "|>",
+              "right": {
+                "type": "BinaryExpression",
+                "start":17,"end":22,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":22}},
+                "left": {
+                  "type": "Identifier",
+                  "start":17,"end":18,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":18},"identifierName":"$"},
+                  "name": "$"
+                },
+                "operator": "+",
+                "right": {
+                  "type": "NumericLiteral",
+                  "start":21,"end":22,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":22}},
+                  "extra": {
+                    "rawValue": 1,
+                    "raw": "1"
+                  },
+                  "value": 1
+                }
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-outer-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-outer-topic/input.js
new file mode 100644
index 000000000000..9f92c6862b1f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-outer-topic/input.js
@@ -0,0 +1 @@
+x |> ($ => $ |> ^^)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-outer-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-outer-topic/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-outer-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-outer-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-outer-topic/output.json
new file mode 100644
index 000000000000..e51b8230caeb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-arrow-function-without-outer-topic/output.json
@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:5)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ArrowFunctionExpression",
+            "start":6,"end":18,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":18}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"$"},
+                "name": "$"
+              }
+            ],
+            "body": {
+              "type": "BinaryExpression",
+              "start":11,"end":18,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":18}},
+              "left": {
+                "type": "Identifier",
+                "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"$"},
+                "name": "$"
+              },
+              "operator": "|>",
+              "right": {
+                "type": "TopicReference",
+                "start":16,"end":18,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":18}}
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-function-call/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-function-call/input.js
new file mode 100644
index 000000000000..ea18fee6db62
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-function-call/input.js
@@ -0,0 +1 @@
+x |> (^^ |> f(^^, x))
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-function-call/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-function-call/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-function-call/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-function-call/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-function-call/output.json
new file mode 100644
index 000000000000..9e38a74f8f60
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-with-function-call/output.json
@@ -0,0 +1,60 @@
+{
+  "type": "File",
+  "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":6,"end":20,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":20}},
+            "left": {
+              "type": "TopicReference",
+              "start":6,"end":8,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":8}}
+            },
+            "operator": "|>",
+            "right": {
+              "type": "CallExpression",
+              "start":12,"end":20,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":20}},
+              "callee": {
+                "type": "Identifier",
+                "start":12,"end":13,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":13},"identifierName":"f"},
+                "name": "f"
+              },
+              "arguments": [
+                {
+                  "type": "TopicReference",
+                  "start":14,"end":16,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":16}}
+                },
+                {
+                  "type": "Identifier",
+                  "start":18,"end":19,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":19},"identifierName":"x"},
+                  "name": "x"
+                }
+              ]
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-inner-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-inner-topic/input.js
new file mode 100644
index 000000000000..9afeed5ee8e1
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-inner-topic/input.js
@@ -0,0 +1 @@
+x |> (^^ |> f())
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-inner-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-inner-topic/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-inner-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-inner-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-inner-topic/output.json
new file mode 100644
index 000000000000..8390963fe8c2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-inner-topic/output.json
@@ -0,0 +1,53 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:12)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":6,"end":15,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":6,"end":8,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":8}}
+            },
+            "operator": "|>",
+            "right": {
+              "type": "CallExpression",
+              "start":12,"end":15,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":15}},
+              "callee": {
+                "type": "Identifier",
+                "start":12,"end":13,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":13},"identifierName":"f"},
+                "name": "f"
+              },
+              "arguments": []
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-outer-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-outer-topic/input.js
new file mode 100644
index 000000000000..9d00837048ed
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-outer-topic/input.js
@@ -0,0 +1 @@
+x |> ($ |> f)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-outer-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-outer-topic/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-outer-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-outer-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-outer-topic/output.json
new file mode 100644
index 000000000000..cfab816d1276
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-nested-pipelines-without-outer-topic/output.json
@@ -0,0 +1,50 @@
+{
+  "type": "File",
+  "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:11)",
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:5)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":6,"end":12,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":12}},
+            "left": {
+              "type": "Identifier",
+              "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"$"},
+              "name": "$"
+            },
+            "operator": "|>",
+            "right": {
+              "type": "Identifier",
+              "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"f"},
+              "name": "f"
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 5
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-class-expression/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-class-expression/input.js
new file mode 100644
index 000000000000..6ccb6ca13351
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-class-expression/input.js
@@ -0,0 +1 @@
+value |> class { }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-class-expression/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-class-expression/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-class-expression/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-class-expression/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-class-expression/output.json
new file mode 100644
index 000000000000..1e904fe3ddea
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-class-expression/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "ClassExpression",
+            "start":9,"end":18,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":18}},
+            "id": null,
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start":15,"end":18,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":18}},
+              "body": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-function-expression/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-function-expression/input.js
new file mode 100644
index 000000000000..faf09879d637
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-function-expression/input.js
@@ -0,0 +1 @@
+value |> function (x) { return; }
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-function-expression/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-function-expression/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-function-expression/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-function-expression/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-function-expression/output.json
new file mode 100644
index 000000000000..4a5325355978
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-no-topic-function-expression/output.json
@@ -0,0 +1,56 @@
+{
+  "type": "File",
+  "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body does not contain a topic reference; Hack-style pipes must use topic at least once. (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "FunctionExpression",
+            "start":9,"end":33,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":33}},
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"x"},
+                "name": "x"
+              }
+            ],
+            "body": {
+              "type": "BlockStatement",
+              "start":22,"end":33,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":33}},
+              "body": [
+                {
+                  "type": "ReturnStatement",
+                  "start":24,"end":31,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":31}},
+                  "argument": null
+                }
+              ],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-non-generator-yield-identifier/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-non-generator-yield-identifier/input.js
new file mode 100644
index 000000000000..1a174774e84c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-non-generator-yield-identifier/input.js
@@ -0,0 +1 @@
+x |> yield + ^^;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-non-generator-yield-identifier/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-non-generator-yield-identifier/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-non-generator-yield-identifier/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-non-generator-yield-identifier/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-non-generator-yield-identifier/output.json
new file mode 100644
index 000000000000..fd8b41311ceb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-non-generator-yield-identifier/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":5,"end":15,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "Identifier",
+              "start":5,"end":10,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":10},"identifierName":"yield"},
+              "name": "yield"
+            },
+            "operator": "+",
+            "right": {
+              "type": "TopicReference",
+              "start":13,"end":15,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":15}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-placeholder-template/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-placeholder-template/input.js
new file mode 100644
index 000000000000..4aa33d979b5a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-placeholder-template/input.js
@@ -0,0 +1 @@
+^^^^FUNCTION^^^^(0, ^^^^VALUE^^^^);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-placeholder-template/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-placeholder-template/options.json
new file mode 100644
index 000000000000..c6b020e739ac
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-placeholder-template/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    "placeholders"
+  ],
+  "throws": "Cannot combine placeholders plugin and Hack-style pipes."
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-private-property-in-private-method/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-private-property-in-private-method/input.js
new file mode 100644
index 000000000000..23ebdd2a9f7b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-private-property-in-private-method/input.js
@@ -0,0 +1,7 @@
+class Thing {
+  #property;
+
+  #method () {
+    value |> this.#property + ^^;
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-private-property-in-private-method/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-private-property-in-private-method/options.json
new file mode 100644
index 000000000000..77d2746d0ac0
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-private-property-in-private-method/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    "classPrivateProperties",
+    "classPrivateMethods"
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-private-property-in-private-method/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-private-property-in-private-method/output.json
new file mode 100644
index 000000000000..9be0015cd858
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-private-property-in-private-method/output.json
@@ -0,0 +1,111 @@
+{
+  "type": "File",
+  "start":0,"end":82,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":82,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":82,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":11,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":11},"identifierName":"Thing"},
+          "name": "Thing"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":12,"end":82,"loc":{"start":{"line":1,"column":12},"end":{"line":7,"column":1}},
+          "body": [
+            {
+              "type": "ClassPrivateProperty",
+              "start":16,"end":26,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":12}},
+              "static": false,
+              "key": {
+                "type": "PrivateName",
+                "start":16,"end":25,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":11}},
+                "id": {
+                  "type": "Identifier",
+                  "start":17,"end":25,"loc":{"start":{"line":2,"column":3},"end":{"line":2,"column":11},"identifierName":"property"},
+                  "name": "property"
+                }
+              },
+              "value": null
+            },
+            {
+              "type": "ClassPrivateMethod",
+              "start":30,"end":80,"loc":{"start":{"line":4,"column":2},"end":{"line":6,"column":3}},
+              "static": false,
+              "key": {
+                "type": "PrivateName",
+                "start":30,"end":37,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":9}},
+                "id": {
+                  "type": "Identifier",
+                  "start":31,"end":37,"loc":{"start":{"line":4,"column":3},"end":{"line":4,"column":9},"identifierName":"method"},
+                  "name": "method"
+                }
+              },
+              "kind": "method",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [],
+              "body": {
+                "type": "BlockStatement",
+                "start":41,"end":80,"loc":{"start":{"line":4,"column":13},"end":{"line":6,"column":3}},
+                "body": [
+                  {
+                    "type": "ExpressionStatement",
+                    "start":47,"end":76,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":33}},
+                    "expression": {
+                      "type": "BinaryExpression",
+                      "start":47,"end":75,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":32}},
+                      "left": {
+                        "type": "Identifier",
+                        "start":47,"end":52,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":9},"identifierName":"value"},
+                        "name": "value"
+                      },
+                      "operator": "|>",
+                      "right": {
+                        "type": "BinaryExpression",
+                        "start":56,"end":75,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":32}},
+                        "left": {
+                          "type": "MemberExpression",
+                          "start":56,"end":70,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":27}},
+                          "object": {
+                            "type": "ThisExpression",
+                            "start":56,"end":60,"loc":{"start":{"line":5,"column":13},"end":{"line":5,"column":17}}
+                          },
+                          "computed": false,
+                          "property": {
+                            "type": "PrivateName",
+                            "start":61,"end":70,"loc":{"start":{"line":5,"column":18},"end":{"line":5,"column":27}},
+                            "id": {
+                              "type": "Identifier",
+                              "start":62,"end":70,"loc":{"start":{"line":5,"column":19},"end":{"line":5,"column":27},"identifierName":"property"},
+                              "name": "property"
+                            }
+                          }
+                        },
+                        "operator": "+",
+                        "right": {
+                          "type": "TopicReference",
+                          "start":73,"end":75,"loc":{"start":{"line":5,"column":30},"end":{"line":5,"column":32}}
+                        }
+                      }
+                    }
+                  }
+                ],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-parenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-parenthesized/input.js
new file mode 100644
index 000000000000..7161ae9f6732
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-parenthesized/input.js
@@ -0,0 +1 @@
+value |> (^^)
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-parenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-parenthesized/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-parenthesized/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-parenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-parenthesized/output.json
new file mode 100644
index 000000000000..81a91c7a1330
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-parenthesized/output.json
@@ -0,0 +1,35 @@
+{
+  "type": "File",
+  "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TopicReference",
+            "start":10,"end":12,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":12}},
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-unparenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-unparenthesized/input.js
new file mode 100644
index 000000000000..ebfd2971b61d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-unparenthesized/input.js
@@ -0,0 +1 @@
+value |> ^^
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-unparenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-unparenthesized/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-unparenthesized/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-unparenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-unparenthesized/output.json
new file mode 100644
index 000000000000..8b15798610ae
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-identity-unparenthesized/output.json
@@ -0,0 +1,31 @@
+{
+  "type": "File",
+  "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TopicReference",
+            "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-then-digit/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-then-digit/input.js
new file mode 100644
index 000000000000..ff677cd47beb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-then-digit/input.js
@@ -0,0 +1 @@
+x |> ^^42;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-then-digit/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-then-digit/options.json
new file mode 100644
index 000000000000..298f226ff26b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-then-digit/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "^^"
+      }
+    ]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-then-digit/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-then-digit/output.json
new file mode 100644
index 000000000000..017aba97749b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-then-digit/output.json
@@ -0,0 +1,47 @@
+{
+  "type": "File",
+  "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+  "errors": [
+    "SyntaxError: Missing semicolon. (1:7)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":7,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":7}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":7,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":7}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "TopicReference",
+            "start":5,"end":7,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":7}}
+          }
+        }
+      },
+      {
+        "type": "ExpressionStatement",
+        "start":7,"end":10,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":10}},
+        "expression": {
+          "type": "NumericLiteral",
+          "start":7,"end":9,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":9}},
+          "extra": {
+            "rawValue": 42,
+            "raw": "42"
+          },
+          "value": 42
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-with-optional-method-call/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-with-optional-method-call/input.js
new file mode 100644
index 000000000000..72d18278ec5d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-with-optional-method-call/input.js
@@ -0,0 +1 @@
+value |> ^^?.method()
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-with-optional-method-call/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-with-optional-method-call/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-with-optional-method-call/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-with-optional-method-call/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-with-optional-method-call/output.json
new file mode 100644
index 000000000000..57270291759b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-topic-with-optional-method-call/output.json
@@ -0,0 +1,48 @@
+{
+  "type": "File",
+  "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "OptionalCallExpression",
+            "start":9,"end":21,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":21}},
+            "callee": {
+              "type": "OptionalMemberExpression",
+              "start":9,"end":19,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":19}},
+              "object": {
+                "type": "TopicReference",
+                "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+              },
+              "computed": false,
+              "property": {
+                "type": "Identifier",
+                "start":13,"end":19,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":19},"identifierName":"method"},
+                "name": "method"
+              },
+              "optional": true
+            },
+            "optional": false,
+            "arguments": []
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-unbound-topic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-unbound-topic/input.js
new file mode 100644
index 000000000000..edf4e3bfb345
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-unbound-topic/input.js
@@ -0,0 +1 @@
+1 + ^^
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-unbound-topic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-unbound-topic/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-unbound-topic/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-unbound-topic/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-unbound-topic/output.json
new file mode 100644
index 000000000000..3c7833aaa15c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-unbound-topic/output.json
@@ -0,0 +1,38 @@
+{
+  "type": "File",
+  "start":0,"end":6,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":6}},
+  "errors": [
+    "SyntaxError: Topic reference is unbound; it must be inside a pipe body. (1:4)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":6,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":6}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":6,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":6}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":6,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":6}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1}},
+            "extra": {
+              "rawValue": 1,
+              "raw": "1"
+            },
+            "value": 1
+          },
+          "operator": "+",
+          "right": {
+            "type": "TopicReference",
+            "start":4,"end":6,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":6}}
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-v8intrinsic/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-v8intrinsic/input.js
new file mode 100644
index 000000000000..4c6a361dae02
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-v8intrinsic/input.js
@@ -0,0 +1 @@
+%GetOptimizationStatus(f);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-v8intrinsic/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-v8intrinsic/options.json
new file mode 100644
index 000000000000..c0c09a4f7f5b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-v8intrinsic/options.json
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }],
+    "v8intrinsic"
+  ],
+  "throws": "Cannot combine v8intrinsic plugin and Hack-style pipes."
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-assignment/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-assignment/input.js
new file mode 100644
index 000000000000..8771f297f7fd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-assignment/input.js
@@ -0,0 +1 @@
+x = 0 |> ^^;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-assignment/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-assignment/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-assignment/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-assignment/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-assignment/output.json
new file mode 100644
index 000000000000..2c30399f40cc
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-assignment/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":12,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":12}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":12,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":12}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":12,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":12}},
+        "expression": {
+          "type": "AssignmentExpression",
+          "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+          "operator": "=",
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "right": {
+            "type": "BinaryExpression",
+            "start":4,"end":11,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":11}},
+            "left": {
+              "type": "NumericLiteral",
+              "start":4,"end":5,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":5}},
+              "extra": {
+                "rawValue": 0,
+                "raw": "0"
+              },
+              "value": 0
+            },
+            "operator": "|>",
+            "right": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-classic-for-statement-init/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-classic-for-statement-init/input.js
new file mode 100644
index 000000000000..88bb77106a1b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-classic-for-statement-init/input.js
@@ -0,0 +1,2 @@
+for (var i = 0 |> ^^; i <= 10; i++)
+  sum = sum + i;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-classic-for-statement-init/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-classic-for-statement-init/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-classic-for-statement-init/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-classic-for-statement-init/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-classic-for-statement-init/output.json
new file mode 100644
index 000000000000..060f5e076bcd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-classic-for-statement-init/output.json
@@ -0,0 +1,110 @@
+{
+  "type": "File",
+  "start":0,"end":52,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":52,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ForStatement",
+        "start":0,"end":52,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":16}},
+        "init": {
+          "type": "VariableDeclaration",
+          "start":5,"end":20,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":20}},
+          "declarations": [
+            {
+              "type": "VariableDeclarator",
+              "start":9,"end":20,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":20}},
+              "id": {
+                "type": "Identifier",
+                "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10},"identifierName":"i"},
+                "name": "i"
+              },
+              "init": {
+                "type": "BinaryExpression",
+                "start":13,"end":20,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":20}},
+                "left": {
+                  "type": "NumericLiteral",
+                  "start":13,"end":14,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":14}},
+                  "extra": {
+                    "rawValue": 0,
+                    "raw": "0"
+                  },
+                  "value": 0
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "TopicReference",
+                  "start":18,"end":20,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":20}}
+                }
+              }
+            }
+          ],
+          "kind": "var"
+        },
+        "test": {
+          "type": "BinaryExpression",
+          "start":22,"end":29,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":29}},
+          "left": {
+            "type": "Identifier",
+            "start":22,"end":23,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":23},"identifierName":"i"},
+            "name": "i"
+          },
+          "operator": "<=",
+          "right": {
+            "type": "NumericLiteral",
+            "start":27,"end":29,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":29}},
+            "extra": {
+              "rawValue": 10,
+              "raw": "10"
+            },
+            "value": 10
+          }
+        },
+        "update": {
+          "type": "UpdateExpression",
+          "start":31,"end":34,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":34}},
+          "operator": "++",
+          "prefix": false,
+          "argument": {
+            "type": "Identifier",
+            "start":31,"end":32,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":32},"identifierName":"i"},
+            "name": "i"
+          }
+        },
+        "body": {
+          "type": "ExpressionStatement",
+          "start":38,"end":52,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":16}},
+          "expression": {
+            "type": "AssignmentExpression",
+            "start":38,"end":51,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":15}},
+            "operator": "=",
+            "left": {
+              "type": "Identifier",
+              "start":38,"end":41,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":5},"identifierName":"sum"},
+              "name": "sum"
+            },
+            "right": {
+              "type": "BinaryExpression",
+              "start":44,"end":51,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":15}},
+              "left": {
+                "type": "Identifier",
+                "start":44,"end":47,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":11},"identifierName":"sum"},
+                "name": "sum"
+              },
+              "operator": "+",
+              "right": {
+                "type": "Identifier",
+                "start":50,"end":51,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":15},"identifierName":"i"},
+                "name": "i"
+              }
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-variable-declaration/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-variable-declaration/input.js
new file mode 100644
index 000000000000..019c6be5d0a5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-variable-declaration/input.js
@@ -0,0 +1 @@
+const x = 0 |> ^^;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-variable-declaration/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-variable-declaration/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-variable-declaration/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-variable-declaration/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-variable-declaration/output.json
new file mode 100644
index 000000000000..2142f35fc204
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-variable-declaration/output.json
@@ -0,0 +1,47 @@
+{
+  "type": "File",
+  "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start":6,"end":17,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":17}},
+            "id": {
+              "type": "Identifier",
+              "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"x"},
+              "name": "x"
+            },
+            "init": {
+              "type": "BinaryExpression",
+              "start":10,"end":17,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":17}},
+              "left": {
+                "type": "NumericLiteral",
+                "start":10,"end":11,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":11}},
+                "extra": {
+                  "rawValue": 0,
+                  "raw": "0"
+                },
+                "value": 0
+              },
+              "operator": "|>",
+              "right": {
+                "type": "TopicReference",
+                "start":15,"end":17,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":17}}
+              }
+            }
+          }
+        ],
+        "kind": "const"
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-with-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-with-spaces/input.js
new file mode 100644
index 000000000000..112609549d43
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-with-spaces/input.js
@@ -0,0 +1 @@
+variable ^= value |> ^^;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-with-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-with-spaces/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-with-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-with-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-with-spaces/output.json
new file mode 100644
index 000000000000..e11c36890aab
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-with-spaces/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+        "expression": {
+          "type": "AssignmentExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "operator": "^=",
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8},"identifierName":"variable"},
+            "name": "variable"
+          },
+          "right": {
+            "type": "BinaryExpression",
+            "start":12,"end":23,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":23}},
+            "left": {
+              "type": "Identifier",
+              "start":12,"end":17,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":17},"identifierName":"value"},
+              "name": "value"
+            },
+            "operator": "|>",
+            "right": {
+              "type": "TopicReference",
+              "start":21,"end":23,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":23}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-without-spaces/input.js
new file mode 100644
index 000000000000..85afbba55aec
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-without-spaces/input.js
@@ -0,0 +1 @@
+variable^=value |> ^^;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-without-spaces/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-without-spaces/output.json
new file mode 100644
index 000000000000..42206068becd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-within-xor-assignment-without-spaces/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
+        "expression": {
+          "type": "AssignmentExpression",
+          "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":21}},
+          "operator": "^=",
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8},"identifierName":"variable"},
+            "name": "variable"
+          },
+          "right": {
+            "type": "BinaryExpression",
+            "start":10,"end":21,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":21}},
+            "left": {
+              "type": "Identifier",
+              "start":10,"end":15,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":15},"identifierName":"value"},
+              "name": "value"
+            },
+            "operator": "|>",
+            "right": {
+              "type": "TopicReference",
+              "start":19,"end":21,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":21}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-with-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-with-spaces/input.js
new file mode 100644
index 000000000000..3604cfbf29d2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-with-spaces/input.js
@@ -0,0 +1 @@
+value |> (variable ^= ^^);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-with-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-with-spaces/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-with-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-with-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-with-spaces/output.json
new file mode 100644
index 000000000000..a0e7f446a38f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-with-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":26}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":25,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":25}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":10,"end":24,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":24}},
+            "operator": "^=",
+            "left": {
+              "type": "Identifier",
+              "start":10,"end":18,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":18},"identifierName":"variable"},
+              "name": "variable"
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":22,"end":24,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":24}}
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-without-spaces/input.js
new file mode 100644
index 000000000000..c20c2ab38deb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-without-spaces/input.js
@@ -0,0 +1 @@
+value |> (variable^=^^);
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-without-spaces/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-without-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-without-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-without-spaces/output.json
new file mode 100644
index 000000000000..b33ab2477fab
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-assignment-without-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":24,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":24}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":23,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":23}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "AssignmentExpression",
+            "start":10,"end":22,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":22}},
+            "operator": "^=",
+            "left": {
+              "type": "Identifier",
+              "start":10,"end":18,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":18},"identifierName":"variable"},
+              "name": "variable"
+            },
+            "right": {
+              "type": "TopicReference",
+              "start":20,"end":22,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":22}}
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-regex-outside-pipe/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-regex-outside-pipe/input.js
new file mode 100644
index 000000000000..036d7337789d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-regex-outside-pipe/input.js
@@ -0,0 +1 @@
+5 ^ /3/g;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-regex-outside-pipe/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-regex-outside-pipe/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-regex-outside-pipe/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-regex-outside-pipe/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-regex-outside-pipe/output.json
new file mode 100644
index 000000000000..43c11bd73817
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-regex-outside-pipe/output.json
@@ -0,0 +1,40 @@
+{
+  "type": "File",
+  "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8}},
+          "left": {
+            "type": "NumericLiteral",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1}},
+            "extra": {
+              "rawValue": 5,
+              "raw": "5"
+            },
+            "value": 5
+          },
+          "operator": "^",
+          "right": {
+            "type": "RegExpLiteral",
+            "start":4,"end":8,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":8}},
+            "extra": {
+              "raw": "/3/g"
+            },
+            "pattern": "3",
+            "flags": "g"
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-with-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-with-spaces/input.js
new file mode 100644
index 000000000000..186e7141188a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-with-spaces/input.js
@@ -0,0 +1 @@
+value |> ^^ ^ 2;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-with-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-with-spaces/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-with-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-with-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-with-spaces/output.json
new file mode 100644
index 000000000000..c870aadc6ed1
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-with-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "TopicReference",
+              "start":9,"end":11,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":11}}
+            },
+            "operator": "^",
+            "right": {
+              "type": "NumericLiteral",
+              "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15}},
+              "extra": {
+                "rawValue": 2,
+                "raw": "2"
+              },
+              "value": 2
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-without-spaces/input.js
new file mode 100644
index 000000000000..6ba5ff57966c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-without-spaces/input.js
@@ -0,0 +1 @@
+value |> ^^^2;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-without-spaces/options.json
new file mode 100644
index 000000000000..c66383ce8ae2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-first-without-spaces/options.json
@@ -0,0 +1,4 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]],
+  "throws": "Unexpected token (1:9)"
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-with-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-with-spaces/input.js
new file mode 100644
index 000000000000..d8b84b6a31ee
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-with-spaces/input.js
@@ -0,0 +1 @@
+value |> 2 ^ ^^;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-with-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-with-spaces/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-with-spaces/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-with-spaces/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-with-spaces/output.json
new file mode 100644
index 000000000000..4b1d7c6ef12b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-with-spaces/output.json
@@ -0,0 +1,45 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":5,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":5},"identifierName":"value"},
+            "name": "value"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":9,"end":15,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "NumericLiteral",
+              "start":9,"end":10,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":10}},
+              "extra": {
+                "rawValue": 2,
+                "raw": "2"
+              },
+              "value": 2
+            },
+            "operator": "^",
+            "right": {
+              "type": "TopicReference",
+              "start":13,"end":15,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":15}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-without-spaces/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-without-spaces/input.js
new file mode 100644
index 000000000000..97b4f3167341
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-without-spaces/input.js
@@ -0,0 +1 @@
+value |> 2^^^;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-without-spaces/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-without-spaces/options.json
new file mode 100644
index 000000000000..9f56158147e2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-xor-topic-last-without-spaces/options.json
@@ -0,0 +1,4 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]],
+  "throws": "Unexpected token (1:10)"
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-parenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-parenthesized/input.js
new file mode 100644
index 000000000000..ebb609847dae
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-parenthesized/input.js
@@ -0,0 +1,3 @@
+function * f (x) {
+  return x |> (yield ^^);
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-parenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-parenthesized/options.json
new file mode 100644
index 000000000000..d58c37da1b57
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-parenthesized/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["pipelineOperator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-parenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-parenthesized/output.json
new file mode 100644
index 000000000000..ce25fc689b94
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-parenthesized/output.json
@@ -0,0 +1,65 @@
+{
+  "type": "File",
+  "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"f"},
+          "name": "f"
+        },
+        "generator": true,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15},"identifierName":"x"},
+            "name": "x"
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":17,"end":46,"loc":{"start":{"line":1,"column":17},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ReturnStatement",
+              "start":21,"end":44,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":25}},
+              "argument": {
+                "type": "BinaryExpression",
+                "start":28,"end":43,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":24}},
+                "left": {
+                  "type": "Identifier",
+                  "start":28,"end":29,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":10},"identifierName":"x"},
+                  "name": "x"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "YieldExpression",
+                  "start":34,"end":42,"loc":{"start":{"line":2,"column":15},"end":{"line":2,"column":23}},
+                  "delegate": false,
+                  "argument": {
+                    "type": "TopicReference",
+                    "start":40,"end":42,"loc":{"start":{"line":2,"column":21},"end":{"line":2,"column":23}}
+                  },
+                  "extra": {
+                    "parenthesized": true,
+                    "parenStart": 33
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-unparenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-unparenthesized/input.js
new file mode 100644
index 000000000000..499a51df8e11
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-unparenthesized/input.js
@@ -0,0 +1,3 @@
+function * f (x) {
+  return x |> yield ^^;
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-unparenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-unparenthesized/options.json
new file mode 100644
index 000000000000..ae184a44d3d5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-unparenthesized/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "^^"
+      }
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-unparenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-unparenthesized/output.json
new file mode 100644
index 000000000000..09bad13154b3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-generator-unparenthesized/output.json
@@ -0,0 +1,64 @@
+{
+  "type": "File",
+  "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: Hack-style pipe body cannot be an unparenthesized yield expression; please wrap it in parentheses. (2:14)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":11,"end":12,"loc":{"start":{"line":1,"column":11},"end":{"line":1,"column":12},"identifierName":"f"},
+          "name": "f"
+        },
+        "generator": true,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15},"identifierName":"x"},
+            "name": "x"
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":17,"end":44,"loc":{"start":{"line":1,"column":17},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ReturnStatement",
+              "start":21,"end":42,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":23}},
+              "argument": {
+                "type": "BinaryExpression",
+                "start":28,"end":41,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":22}},
+                "left": {
+                  "type": "Identifier",
+                  "start":28,"end":29,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":10},"identifierName":"x"},
+                  "name": "x"
+                },
+                "operator": "|>",
+                "right": {
+                  "type": "YieldExpression",
+                  "start":33,"end":41,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":22}},
+                  "delegate": false,
+                  "argument": {
+                    "type": "TopicReference",
+                    "start":39,"end":41,"loc":{"start":{"line":2,"column":20},"end":{"line":2,"column":22}}
+                  }
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-identifier-unparenthesized/input.js b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-identifier-unparenthesized/input.js
new file mode 100644
index 000000000000..1a174774e84c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-identifier-unparenthesized/input.js
@@ -0,0 +1 @@
+x |> yield + ^^;
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-identifier-unparenthesized/options.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-identifier-unparenthesized/options.json
new file mode 100644
index 000000000000..298f226ff26b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-identifier-unparenthesized/options.json
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "pipelineOperator",
+      {
+        "proposal": "hack",
+        "topicToken": "^^"
+      }
+    ]
+  ]
+}
diff --git a/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-identifier-unparenthesized/output.json b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-identifier-unparenthesized/output.json
new file mode 100644
index 000000000000..fd8b41311ceb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/experimental/pipeline-operator/hack-double-caret-proposal-yield-identifier-unparenthesized/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":16,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":16}},
+        "expression": {
+          "type": "BinaryExpression",
+          "start":0,"end":15,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":15}},
+          "left": {
+            "type": "Identifier",
+            "start":0,"end":1,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":1},"identifierName":"x"},
+            "name": "x"
+          },
+          "operator": "|>",
+          "right": {
+            "type": "BinaryExpression",
+            "start":5,"end":15,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":15}},
+            "left": {
+              "type": "Identifier",
+              "start":5,"end":10,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":10},"identifierName":"yield"},
+              "name": "yield"
+            },
+            "operator": "+",
+            "right": {
+              "type": "TopicReference",
+              "start":13,"end":15,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":15}}
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/exec.js
new file mode 100644
index 000000000000..a3857da1d980
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/exec.js
@@ -0,0 +1,8 @@
+const expectedValue = 42;
+
+function decorator () {}
+
+const result = expectedValue
+  |> @decorator class { constructor () { this.value = @@; } };
+
+expect((new result).value).toBe(expectedValue);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/input.js
new file mode 100644
index 000000000000..2ac9913e95d2
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/input.js
@@ -0,0 +1,11 @@
+const expectedValue = 42;
+
+function decorator (target) {
+  target.decoratorValue = expectedValue;
+}
+
+const result = expectedValue
+  |> @decorator class { constructor () { this.value = @@; } };
+
+expect(result.decoratorValue).toBe(expectedValue);
+expect((new result).value).toBe(expectedValue);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/options.json
new file mode 100644
index 000000000000..d9bc8f93e7d4
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "@@" }],
+    ["proposal-decorators", { "decoratorsBeforeExport": false }]
+  ]
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/output.js
new file mode 100644
index 000000000000..743b6624c395
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/class-decorator/output.js
@@ -0,0 +1,27 @@
+var _ref;
+
+const expectedValue = 42;
+
+function decorator(target) {
+  target.decoratorValue = expectedValue;
+}
+
+const result = (_ref = expectedValue, babelHelpers.decorate([decorator], function (_initialize) {
+  "use strict";
+
+  class _class {
+    constructor() {
+      _initialize(this);
+
+      this.value = _ref;
+    }
+
+  }
+
+  return {
+    F: _class,
+    d: []
+  };
+}));
+expect(result.decoratorValue).toBe(expectedValue);
+expect(new result().value).toBe(expectedValue);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/hash-tuple/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/hash-tuple/input.js
new file mode 100644
index 000000000000..81a3b28d74df
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/hash-tuple/input.js
@@ -0,0 +1,2 @@
+#[0];
+1 |> #[0, @@];
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/hash-tuple/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/hash-tuple/options.json
new file mode 100644
index 000000000000..0e8928650c99
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/hash-tuple/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "@@" }],
+    ["proposal-record-and-tuple", { "syntaxType": "hash" }]
+  ]
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/hash-tuple/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/hash-tuple/output.js
new file mode 100644
index 000000000000..877d41141fbe
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/hash-tuple/output.js
@@ -0,0 +1,4 @@
+var _ref;
+
+Tuple(0);
+_ref = 1, Tuple(0, _ref);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/options.json
new file mode 100644
index 000000000000..f67a1804515d
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "@@" }]]
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-identity/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-identity/exec.js
new file mode 100644
index 000000000000..3fe1f21a8ca5
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-identity/exec.js
@@ -0,0 +1,3 @@
+const result = 5 |> @@;
+
+expect(result).toBe(5);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-identity/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-identity/input.js
new file mode 100644
index 000000000000..3fe1f21a8ca5
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-identity/input.js
@@ -0,0 +1,3 @@
+const result = 5 |> @@;
+
+expect(result).toBe(5);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-identity/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-identity/output.js
new file mode 100644
index 000000000000..ab1b47369050
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-identity/output.js
@@ -0,0 +1,4 @@
+var _ref;
+
+const result = (_ref = 5, _ref);
+expect(result).toBe(5);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-addition/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-addition/exec.js
new file mode 100644
index 000000000000..787c506985e2
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-addition/exec.js
@@ -0,0 +1,3 @@
+const result = 5 |> @@ + 1 |> @@ + @@;
+
+expect(result).toBe(12);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-addition/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-addition/input.js
new file mode 100644
index 000000000000..787c506985e2
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-addition/input.js
@@ -0,0 +1,3 @@
+const result = 5 |> @@ + 1 |> @@ + @@;
+
+expect(result).toBe(12);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-addition/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-addition/output.js
new file mode 100644
index 000000000000..62a22e6b7067
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-addition/output.js
@@ -0,0 +1,4 @@
+var _ref, _ref2;
+
+const result = (_ref2 = 5, (_ref = _ref2 + 1, _ref + _ref));
+expect(result).toBe(12);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function-and-nested-pipe/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function-and-nested-pipe/exec.js
new file mode 100644
index 000000000000..b9285c2183c9
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function-and-nested-pipe/exec.js
@@ -0,0 +1,9 @@
+const result = 5
+  |> Math.pow(@@, 2)
+  |> [1, 2, 3].map(n => n + @@
+    |> @@ * 2
+    |> `${@@} apples`
+    |> @@.toUpperCase())
+  |> @@.join();
+
+expect(result).toEqual('52 APPLES,54 APPLES,56 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function-and-nested-pipe/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function-and-nested-pipe/input.js
new file mode 100644
index 000000000000..b9285c2183c9
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function-and-nested-pipe/input.js
@@ -0,0 +1,9 @@
+const result = 5
+  |> Math.pow(@@, 2)
+  |> [1, 2, 3].map(n => n + @@
+    |> @@ * 2
+    |> `${@@} apples`
+    |> @@.toUpperCase())
+  |> @@.join();
+
+expect(result).toEqual('52 APPLES,54 APPLES,56 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function-and-nested-pipe/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function-and-nested-pipe/output.js
new file mode 100644
index 000000000000..bf1fcd321aef
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function-and-nested-pipe/output.js
@@ -0,0 +1,8 @@
+var _ref4, _ref5, _ref6;
+
+const result = (_ref6 = 5, (_ref5 = Math.pow(_ref6, 2), (_ref4 = [1, 2, 3].map(n => {
+  var _ref, _ref2, _ref3;
+
+  return _ref3 = n + _ref5, (_ref2 = _ref3 * 2, (_ref = `${_ref2} apples`, _ref.toUpperCase()));
+}), _ref4.join())));
+expect(result).toEqual('52 APPLES,54 APPLES,56 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function/exec.js
new file mode 100644
index 000000000000..977bad252552
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function/exec.js
@@ -0,0 +1,6 @@
+const result = -2.2 // -2.2
+  |> Math.floor(@@) // -3
+  |> (() => Math.pow(@@, 5)) // () => -243
+  |> @@(); // -243
+
+expect(result).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function/input.js
new file mode 100644
index 000000000000..977bad252552
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function/input.js
@@ -0,0 +1,6 @@
+const result = -2.2 // -2.2
+  |> Math.floor(@@) // -3
+  |> (() => Math.pow(@@, 5)) // () => -243
+  |> @@(); // -243
+
+expect(result).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function/output.js
new file mode 100644
index 000000000000..5def3730d465
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-arrow-function/output.js
@@ -0,0 +1,8 @@
+var _ref, _ref2, _ref3;
+
+const result = (_ref3 = -2.2 // -2.2
+, (_ref2 = Math.floor(_ref3) // -3
+, (_ref = () => Math.pow(_ref2, 5) // () => -243
+, _ref()))); // -243
+
+expect(result).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/exec.js
new file mode 100644
index 000000000000..41eba6c4b2f8
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/exec.js
@@ -0,0 +1,14 @@
+function triple (x) {
+  return x * 3
+}
+
+async function asyncFunction(n) {
+  return n
+    |> Math.abs(@@)
+    |> await Promise.resolve(@@)
+    |> triple(@@);
+}
+
+asyncFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/input.js
new file mode 100644
index 000000000000..41eba6c4b2f8
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/input.js
@@ -0,0 +1,14 @@
+function triple (x) {
+  return x * 3
+}
+
+async function asyncFunction(n) {
+  return n
+    |> Math.abs(@@)
+    |> await Promise.resolve(@@)
+    |> triple(@@);
+}
+
+asyncFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/options.json
new file mode 100644
index 000000000000..f19c36b8eef1
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/options.json
@@ -0,0 +1,6 @@
+{
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  },
+  "minNodeVersion": "8.0.0"
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/output.js
new file mode 100644
index 000000000000..aa3d4e62d419
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-await/output.js
@@ -0,0 +1,13 @@
+function triple(x) {
+  return x * 3;
+}
+
+async function asyncFunction(n) {
+  var _ref, _ref2, _ref3;
+
+  return _ref3 = n, (_ref2 = Math.abs(_ref3), (_ref = await Promise.resolve(_ref2), triple(_ref)));
+}
+
+asyncFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/exec.js
new file mode 100644
index 000000000000..f156fd4aff7b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/exec.js
@@ -0,0 +1,20 @@
+const result = 1
+ |> class {
+    #baz;
+
+    constructor () {
+      this.#baz = @@;
+    }
+
+    #bar () {
+      return this.#baz + 2;
+    }
+
+    foo () {
+      return this.#bar() + 3;
+    }
+ }
+ |> new @@
+ |> @@.foo();
+
+expect(result).toBe(1 + 2 + 3);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/input.js
new file mode 100644
index 000000000000..f156fd4aff7b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/input.js
@@ -0,0 +1,20 @@
+const result = 1
+ |> class {
+    #baz;
+
+    constructor () {
+      this.#baz = @@;
+    }
+
+    #bar () {
+      return this.#baz + 2;
+    }
+
+    foo () {
+      return this.#bar() + 3;
+    }
+ }
+ |> new @@
+ |> @@.foo();
+
+expect(result).toBe(1 + 2 + 3);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/options.json
new file mode 100644
index 000000000000..90347a43739e
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "@@" }]
+  ],
+  "minNodeVersion": "14.0.0"
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/output.js
new file mode 100644
index 000000000000..638f9cda750f
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-class-expression-and-private-properties/output.js
@@ -0,0 +1,19 @@
+var _ref, _ref2, _ref3;
+
+const result = (_ref3 = 1, (_ref2 = class {
+  #baz;
+
+  constructor() {
+    this.#baz = _ref3;
+  }
+
+  #bar() {
+    return this.#baz + 2;
+  }
+
+  foo() {
+    return this.#bar() + 3;
+  }
+
+}, (_ref = new _ref2(), _ref.foo())));
+expect(result).toBe(1 + 2 + 3);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-eval/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-eval/exec.js
new file mode 100644
index 000000000000..60e9821df70e
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-eval/exec.js
@@ -0,0 +1,4 @@
+const program = '(function() { return this; })()';
+const result = program |> eval(@@);
+
+expect(result).not.toBeUndefined();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-eval/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-eval/input.js
new file mode 100644
index 000000000000..60e9821df70e
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-eval/input.js
@@ -0,0 +1,4 @@
+const program = '(function() { return this; })()';
+const result = program |> eval(@@);
+
+expect(result).not.toBeUndefined();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-eval/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-eval/output.js
new file mode 100644
index 000000000000..c5dbd6107a44
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-eval/output.js
@@ -0,0 +1,5 @@
+var _ref;
+
+const program = '(function() { return this; })()';
+const result = (_ref = program, eval(_ref));
+expect(result).not.toBeUndefined();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-nested-pipe/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-nested-pipe/exec.js
new file mode 100644
index 000000000000..203f3a0728c1
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-nested-pipe/exec.js
@@ -0,0 +1,7 @@
+const result = 5
+  |> Math.pow(@@, 2)
+  |> (@@ + 1
+    |> `${@@} apples`
+    |> @@.toUpperCase());
+
+expect(result).toEqual('26 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-nested-pipe/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-nested-pipe/input.js
new file mode 100644
index 000000000000..203f3a0728c1
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-nested-pipe/input.js
@@ -0,0 +1,7 @@
+const result = 5
+  |> Math.pow(@@, 2)
+  |> (@@ + 1
+    |> `${@@} apples`
+    |> @@.toUpperCase());
+
+expect(result).toEqual('26 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-nested-pipe/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-nested-pipe/output.js
new file mode 100644
index 000000000000..8ee6b4bbf42f
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-nested-pipe/output.js
@@ -0,0 +1,4 @@
+var _ref, _ref2, _ref3, _ref4;
+
+const result = (_ref4 = 5, (_ref3 = Math.pow(_ref4, 2), (_ref2 = _ref3 + 1, (_ref = `${_ref2} apples`, _ref.toUpperCase()))));
+expect(result).toEqual('26 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-object-literal/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-object-literal/exec.js
new file mode 100644
index 000000000000..c646257782ef
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-object-literal/exec.js
@@ -0,0 +1,10 @@
+function area(rect) {
+  return rect.width * rect.height;
+}
+
+const result = -5
+  |> Math.abs(@@)
+  |> { width: @@, height: @@ + 3 }
+  |> area(@@);
+
+expect(result).toBe(40);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-object-literal/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-object-literal/input.js
new file mode 100644
index 000000000000..c646257782ef
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-object-literal/input.js
@@ -0,0 +1,10 @@
+function area(rect) {
+  return rect.width * rect.height;
+}
+
+const result = -5
+  |> Math.abs(@@)
+  |> { width: @@, height: @@ + 3 }
+  |> area(@@);
+
+expect(result).toBe(40);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-object-literal/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-object-literal/output.js
new file mode 100644
index 000000000000..cd74f2422e0a
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-object-literal/output.js
@@ -0,0 +1,11 @@
+var _ref, _ref2, _ref3;
+
+function area(rect) {
+  return rect.width * rect.height;
+}
+
+const result = (_ref3 = -5, (_ref2 = Math.abs(_ref3), (_ref = {
+  width: _ref2,
+  height: _ref2 + 3
+}, area(_ref))));
+expect(result).toBe(40);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-topic-method-call/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-topic-method-call/exec.js
new file mode 100644
index 000000000000..9b7123ad6c7c
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-topic-method-call/exec.js
@@ -0,0 +1,3 @@
+const result = 'Hello' |> @@.toUpperCase();
+
+expect(result).toBe('HELLO');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-topic-method-call/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-topic-method-call/input.js
new file mode 100644
index 000000000000..9b7123ad6c7c
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-topic-method-call/input.js
@@ -0,0 +1,3 @@
+const result = 'Hello' |> @@.toUpperCase();
+
+expect(result).toBe('HELLO');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-topic-method-call/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-topic-method-call/output.js
new file mode 100644
index 000000000000..029efa564267
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-topic-method-call/output.js
@@ -0,0 +1,4 @@
+var _ref;
+
+const result = (_ref = 'Hello', _ref.toUpperCase());
+expect(result).toBe('HELLO');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-yield/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-yield/exec.js
new file mode 100644
index 000000000000..4d5b6e452e33
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-yield/exec.js
@@ -0,0 +1,13 @@
+function *myGenerator(n) {
+  return n
+  |> (yield @@)
+  |> Math.abs(@@);
+}
+
+const myIterator = myGenerator(15);
+
+const yieldedValue = myIterator.next().value;
+const returnedValue = myIterator.next(-30).value;
+
+expect(yieldedValue).toBe(15);
+expect(returnedValue).toBe(30);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-yield/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-yield/input.js
new file mode 100644
index 000000000000..4d5b6e452e33
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-yield/input.js
@@ -0,0 +1,13 @@
+function *myGenerator(n) {
+  return n
+  |> (yield @@)
+  |> Math.abs(@@);
+}
+
+const myIterator = myGenerator(15);
+
+const yieldedValue = myIterator.next().value;
+const returnedValue = myIterator.next(-30).value;
+
+expect(yieldedValue).toBe(15);
+expect(returnedValue).toBe(30);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-yield/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-yield/output.js
new file mode 100644
index 000000000000..40f127c27ae2
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-body-with-yield/output.js
@@ -0,0 +1,11 @@
+function* myGenerator(n) {
+  var _ref, _ref2;
+
+  return _ref2 = n, (_ref = yield _ref2, Math.abs(_ref));
+}
+
+const myIterator = myGenerator(15);
+const yieldedValue = myIterator.next().value;
+const returnedValue = myIterator.next(-30).value;
+expect(yieldedValue).toBe(15);
+expect(returnedValue).toBe(30);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-head-with-nested-pipe/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-head-with-nested-pipe/exec.js
new file mode 100644
index 000000000000..5513250d4d6c
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-head-with-nested-pipe/exec.js
@@ -0,0 +1,3 @@
+const result = (5 |> Math.pow(@@, 2)) |> @@ + 1;
+
+expect(result).toEqual(26);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-head-with-nested-pipe/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-head-with-nested-pipe/input.js
new file mode 100644
index 000000000000..5513250d4d6c
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-head-with-nested-pipe/input.js
@@ -0,0 +1,3 @@
+const result = (5 |> Math.pow(@@, 2)) |> @@ + 1;
+
+expect(result).toEqual(26);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-head-with-nested-pipe/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-head-with-nested-pipe/output.js
new file mode 100644
index 000000000000..1adde6582021
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-head-with-nested-pipe/output.js
@@ -0,0 +1,4 @@
+var _ref, _ref2;
+
+const result = (_ref2 = (_ref = 5, Math.pow(_ref, 2)), _ref2 + 1);
+expect(result).toEqual(26);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-in-arrow-function/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-in-arrow-function/exec.js
new file mode 100644
index 000000000000..145a9ca45f61
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-in-arrow-function/exec.js
@@ -0,0 +1,6 @@
+const result = () => -2.2 // -2.2
+  |> Math.floor(@@) // -3
+  |> (() => Math.pow(@@, 5)) // () => -243
+  |> @@(); // -243
+
+expect(result()).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-in-arrow-function/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-in-arrow-function/input.js
new file mode 100644
index 000000000000..145a9ca45f61
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-in-arrow-function/input.js
@@ -0,0 +1,6 @@
+const result = () => -2.2 // -2.2
+  |> Math.floor(@@) // -3
+  |> (() => Math.pow(@@, 5)) // () => -243
+  |> @@(); // -243
+
+expect(result()).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-in-arrow-function/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-in-arrow-function/output.js
new file mode 100644
index 000000000000..66106a985d16
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/pipe-in-arrow-function/output.js
@@ -0,0 +1,11 @@
+const result = () => {
+  var _ref, _ref2, _ref3;
+
+  return _ref3 = -2.2 // -2.2
+  , (_ref2 = Math.floor(_ref3) // -3
+  , (_ref = () => Math.pow(_ref2, 5) // () => -243
+  , _ref()));
+}; // -243
+
+
+expect(result()).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/exec.js
new file mode 100644
index 000000000000..ede4f00aa651
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/exec.js
@@ -0,0 +1,5 @@
+const triple = x => x * 3;
+
+const result = -7 |> Math.abs(@@) |> triple(@@);
+
+return expect(result).toBe(21);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/input.js
new file mode 100644
index 000000000000..ede4f00aa651
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/input.js
@@ -0,0 +1,5 @@
+const triple = x => x * 3;
+
+const result = -7 |> Math.abs(@@) |> triple(@@);
+
+return expect(result).toBe(21);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/options.json
new file mode 100644
index 000000000000..fdea82c9bef5
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/options.json
@@ -0,0 +1,9 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "@@" }],
+    "transform-arrow-functions"
+  ],
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  }
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/output.js
new file mode 100644
index 000000000000..23cdd3fe2a2b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-arrow-functions/output.js
@@ -0,0 +1,8 @@
+var _ref, _ref2;
+
+const triple = function (x) {
+  return x * 3;
+};
+
+const result = (_ref2 = -7, (_ref = Math.abs(_ref2), triple(_ref)));
+return expect(result).toBe(21);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/exec.js
new file mode 100644
index 000000000000..11bcbe57a5c2
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/exec.js
@@ -0,0 +1,13 @@
+const triple = (x) => x * 3;
+
+async function myFunction(n) {
+  return n
+    |> Math.abs(@@)
+    |> Promise.resolve(@@)
+    |> await @@
+    |> triple(@@);
+}
+
+return myFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/input.js
new file mode 100644
index 000000000000..11bcbe57a5c2
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/input.js
@@ -0,0 +1,13 @@
+const triple = (x) => x * 3;
+
+async function myFunction(n) {
+  return n
+    |> Math.abs(@@)
+    |> Promise.resolve(@@)
+    |> await @@
+    |> triple(@@);
+}
+
+return myFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/options.json
new file mode 100644
index 000000000000..3236584245d3
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/options.json
@@ -0,0 +1,10 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "@@" }],
+    "transform-arrow-functions"
+  ],
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  },
+  "minNodeVersion": "8.0.0"
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/output.js
new file mode 100644
index 000000000000..3a32f6e23831
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/transform-await-and-arrow-functions/output.js
@@ -0,0 +1,13 @@
+const triple = function (x) {
+  return x * 3;
+};
+
+async function myFunction(n) {
+  var _ref, _ref2, _ref3, _ref4;
+
+  return _ref4 = n, (_ref3 = Math.abs(_ref4), (_ref2 = Promise.resolve(_ref3), (_ref = await _ref2, triple(_ref))));
+}
+
+return myFunction(-7).then(function (result) {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/while-statement-with-pipe-in-condition/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/while-statement-with-pipe-in-condition/exec.js
new file mode 100644
index 000000000000..4e676936116b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/while-statement-with-pipe-in-condition/exec.js
@@ -0,0 +1,7 @@
+let i = 0;
+let sum = 0;
+
+while (i |> (i = @@ + 1) |> @@ <= 10)
+  sum += i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/while-statement-with-pipe-in-condition/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/while-statement-with-pipe-in-condition/input.js
new file mode 100644
index 000000000000..4e676936116b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/while-statement-with-pipe-in-condition/input.js
@@ -0,0 +1,7 @@
+let i = 0;
+let sum = 0;
+
+while (i |> (i = @@ + 1) |> @@ <= 10)
+  sum += i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/while-statement-with-pipe-in-condition/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/while-statement-with-pipe-in-condition/output.js
new file mode 100644
index 000000000000..0622dfee4902
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/while-statement-with-pipe-in-condition/output.js
@@ -0,0 +1,10 @@
+let i = 0;
+let sum = 0;
+
+while (_ref2 = i, (_ref = i = _ref2 + 1, _ref <= 10)) {
+  var _ref, _ref2;
+
+  sum += i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-assignment/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-assignment/exec.js
new file mode 100644
index 000000000000..dedb84b3374a
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-assignment/exec.js
@@ -0,0 +1,3 @@
+const x = 0 |> @@ + 1;
+
+expect(x).toBe(1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-assignment/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-assignment/input.js
new file mode 100644
index 000000000000..dedb84b3374a
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-assignment/input.js
@@ -0,0 +1,3 @@
+const x = 0 |> @@ + 1;
+
+expect(x).toBe(1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-assignment/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-assignment/output.js
new file mode 100644
index 000000000000..5ca2ce9e5390
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-assignment/output.js
@@ -0,0 +1,4 @@
+var _ref;
+
+const x = (_ref = 0, _ref + 1);
+expect(x).toBe(1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-init/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-init/exec.js
new file mode 100644
index 000000000000..10982a809f34
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-init/exec.js
@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0 |> @@; i <= 10; i++)
+  sum += i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-init/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-init/input.js
new file mode 100644
index 000000000000..10982a809f34
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-init/input.js
@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0 |> @@; i <= 10; i++)
+  sum += i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-init/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-init/output.js
new file mode 100644
index 000000000000..dd399138c6fb
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-init/output.js
@@ -0,0 +1,9 @@
+let sum = 0;
+
+for (var i = (_ref = 0, _ref); i <= 10; i++) {
+  var _ref;
+
+  sum += i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-test/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-test/exec.js
new file mode 100644
index 000000000000..97f7d9b45e87
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-test/exec.js
@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0; i |> @@ <= 10; i++)
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-test/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-test/input.js
new file mode 100644
index 000000000000..97f7d9b45e87
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-test/input.js
@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0; i |> @@ <= 10; i++)
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-test/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-test/output.js
new file mode 100644
index 000000000000..14ae06d74abf
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-test/output.js
@@ -0,0 +1,9 @@
+let sum = 0;
+
+for (var i = 0; _ref = i, _ref <= 10; i++) {
+  var _ref;
+
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-update/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-update/exec.js
new file mode 100644
index 000000000000..b174fbec0f29
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-update/exec.js
@@ -0,0 +1,6 @@
+let sum = 0;
+for (var i = 0; i <= 10; i = i |> @@ + 1) {
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-update/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-update/input.js
new file mode 100644
index 000000000000..b174fbec0f29
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-update/input.js
@@ -0,0 +1,6 @@
+let sum = 0;
+for (var i = 0; i <= 10; i = i |> @@ + 1) {
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-update/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-update/output.js
new file mode 100644
index 000000000000..a741096b130d
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-for-classic-statement-update/output.js
@@ -0,0 +1,9 @@
+let sum = 0;
+
+for (var i = 0; i <= 10; i = (_ref = i, _ref + 1)) {
+  var _ref;
+
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-generator-with-yield/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-generator-with-yield/input.js
new file mode 100644
index 000000000000..6d4009378926
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-generator-with-yield/input.js
@@ -0,0 +1,5 @@
+function * myGenerator(n) {
+  return n
+    |> (yield @@)
+    |> Math.abs(@@);
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-generator-with-yield/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-generator-with-yield/output.js
new file mode 100644
index 000000000000..4e9cfe3a1240
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-generator-with-yield/output.js
@@ -0,0 +1,5 @@
+function* myGenerator(n) {
+  var _ref, _ref2;
+
+  return _ref2 = n, (_ref = yield _ref2, Math.abs(_ref));
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-if-else-block/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-if-else-block/input.js
new file mode 100644
index 000000000000..107b765823de
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-if-else-block/input.js
@@ -0,0 +1,4 @@
+if (v |> e(@@) |> f(@@))
+  g() |> h(@@, @@ + 1) |> i(@@);
+else
+  j();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-if-else-block/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-if-else-block/output.js
new file mode 100644
index 000000000000..5d542dc97ffc
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-if-else-block/output.js
@@ -0,0 +1,3 @@
+var _ref, _ref2, _ref3, _ref4;
+
+if (_ref2 = v, (_ref = e(_ref2), f(_ref))) _ref4 = g(), (_ref3 = h(_ref4, _ref4 + 1), i(_ref3));else j();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-var-statement/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-var-statement/exec.js
new file mode 100644
index 000000000000..26837dd5150f
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-var-statement/exec.js
@@ -0,0 +1,3 @@
+var i = 0;
+
+expect(i).toBe(0);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-var-statement/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-var-statement/input.js
new file mode 100644
index 000000000000..26837dd5150f
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-var-statement/input.js
@@ -0,0 +1,3 @@
+var i = 0;
+
+expect(i).toBe(0);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-var-statement/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-var-statement/output.js
new file mode 100644
index 000000000000..126fd403042b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-at/within-var-statement/output.js
@@ -0,0 +1,2 @@
+var i = 0;
+expect(i).toBe(0);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/exec.js
new file mode 100644
index 000000000000..c41b3898e235
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/exec.js
@@ -0,0 +1,8 @@
+const expectedValue = 42;
+
+function decorator () {}
+
+const result = expectedValue
+  |> @decorator class { constructor () { this.value = ^^; } };
+
+expect((new result).value).toBe(expectedValue);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/input.js
new file mode 100644
index 000000000000..7567377fa7a7
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/input.js
@@ -0,0 +1,11 @@
+const expectedValue = 42;
+
+function decorator (target) {
+  target.decoratorValue = expectedValue;
+}
+
+const result = expectedValue
+  |> @decorator class { constructor () { this.value = ^^; } };
+
+expect(result.decoratorValue).toBe(expectedValue);
+expect((new result).value).toBe(expectedValue);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/options.json
new file mode 100644
index 000000000000..15526f1d0636
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "^^" }],
+    ["proposal-decorators", { "decoratorsBeforeExport": false }]
+  ]
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/output.js
new file mode 100644
index 000000000000..743b6624c395
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/class-decorator/output.js
@@ -0,0 +1,27 @@
+var _ref;
+
+const expectedValue = 42;
+
+function decorator(target) {
+  target.decoratorValue = expectedValue;
+}
+
+const result = (_ref = expectedValue, babelHelpers.decorate([decorator], function (_initialize) {
+  "use strict";
+
+  class _class {
+    constructor() {
+      _initialize(this);
+
+      this.value = _ref;
+    }
+
+  }
+
+  return {
+    F: _class,
+    d: []
+  };
+}));
+expect(result.decoratorValue).toBe(expectedValue);
+expect(new result().value).toBe(expectedValue);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/hash-tuple/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/hash-tuple/input.js
new file mode 100644
index 000000000000..5a6ea279ee6f
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/hash-tuple/input.js
@@ -0,0 +1,2 @@
+#[0];
+1 |> #[0, ^^];
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/hash-tuple/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/hash-tuple/options.json
new file mode 100644
index 000000000000..2c2a31351921
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/hash-tuple/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "^^" }],
+    ["proposal-record-and-tuple", { "syntaxType": "hash" }]
+  ]
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/hash-tuple/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/hash-tuple/output.js
new file mode 100644
index 000000000000..877d41141fbe
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/hash-tuple/output.js
@@ -0,0 +1,4 @@
+var _ref;
+
+Tuple(0);
+_ref = 1, Tuple(0, _ref);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/options.json
new file mode 100644
index 000000000000..5369c8cfb068
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": [["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "^^" }]]
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-identity/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-identity/exec.js
new file mode 100644
index 000000000000..a41e6d5c70ce
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-identity/exec.js
@@ -0,0 +1,3 @@
+const result = 5 |> ^^;
+
+expect(result).toBe(5);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-identity/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-identity/input.js
new file mode 100644
index 000000000000..a41e6d5c70ce
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-identity/input.js
@@ -0,0 +1,3 @@
+const result = 5 |> ^^;
+
+expect(result).toBe(5);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-identity/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-identity/output.js
new file mode 100644
index 000000000000..ab1b47369050
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-identity/output.js
@@ -0,0 +1,4 @@
+var _ref;
+
+const result = (_ref = 5, _ref);
+expect(result).toBe(5);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-addition/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-addition/exec.js
new file mode 100644
index 000000000000..e8f7dd54ac2a
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-addition/exec.js
@@ -0,0 +1,3 @@
+const result = 5 |> ^^ + 1 |> ^^ + ^^;
+
+expect(result).toBe(12);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-addition/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-addition/input.js
new file mode 100644
index 000000000000..e8f7dd54ac2a
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-addition/input.js
@@ -0,0 +1,3 @@
+const result = 5 |> ^^ + 1 |> ^^ + ^^;
+
+expect(result).toBe(12);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-addition/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-addition/output.js
new file mode 100644
index 000000000000..62a22e6b7067
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-addition/output.js
@@ -0,0 +1,4 @@
+var _ref, _ref2;
+
+const result = (_ref2 = 5, (_ref = _ref2 + 1, _ref + _ref));
+expect(result).toBe(12);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function-and-nested-pipe/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function-and-nested-pipe/exec.js
new file mode 100644
index 000000000000..221d2065dfa4
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function-and-nested-pipe/exec.js
@@ -0,0 +1,9 @@
+const result = 5
+  |> Math.pow(^^, 2)
+  |> [1, 2, 3].map(n => n + ^^
+    |> ^^ * 2
+    |> `${^^} apples`
+    |> ^^.toUpperCase())
+  |> ^^.join();
+
+expect(result).toEqual('52 APPLES,54 APPLES,56 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function-and-nested-pipe/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function-and-nested-pipe/input.js
new file mode 100644
index 000000000000..221d2065dfa4
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function-and-nested-pipe/input.js
@@ -0,0 +1,9 @@
+const result = 5
+  |> Math.pow(^^, 2)
+  |> [1, 2, 3].map(n => n + ^^
+    |> ^^ * 2
+    |> `${^^} apples`
+    |> ^^.toUpperCase())
+  |> ^^.join();
+
+expect(result).toEqual('52 APPLES,54 APPLES,56 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function-and-nested-pipe/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function-and-nested-pipe/output.js
new file mode 100644
index 000000000000..bf1fcd321aef
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function-and-nested-pipe/output.js
@@ -0,0 +1,8 @@
+var _ref4, _ref5, _ref6;
+
+const result = (_ref6 = 5, (_ref5 = Math.pow(_ref6, 2), (_ref4 = [1, 2, 3].map(n => {
+  var _ref, _ref2, _ref3;
+
+  return _ref3 = n + _ref5, (_ref2 = _ref3 * 2, (_ref = `${_ref2} apples`, _ref.toUpperCase()));
+}), _ref4.join())));
+expect(result).toEqual('52 APPLES,54 APPLES,56 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function/exec.js
new file mode 100644
index 000000000000..885448c3496b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function/exec.js
@@ -0,0 +1,6 @@
+const result = -2.2 // -2.2
+  |> Math.floor(^^) // -3
+  |> (() => Math.pow(^^, 5)) // () => -243
+  |> ^^(); // -243
+
+expect(result).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function/input.js
new file mode 100644
index 000000000000..885448c3496b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function/input.js
@@ -0,0 +1,6 @@
+const result = -2.2 // -2.2
+  |> Math.floor(^^) // -3
+  |> (() => Math.pow(^^, 5)) // () => -243
+  |> ^^(); // -243
+
+expect(result).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function/output.js
new file mode 100644
index 000000000000..5def3730d465
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-arrow-function/output.js
@@ -0,0 +1,8 @@
+var _ref, _ref2, _ref3;
+
+const result = (_ref3 = -2.2 // -2.2
+, (_ref2 = Math.floor(_ref3) // -3
+, (_ref = () => Math.pow(_ref2, 5) // () => -243
+, _ref()))); // -243
+
+expect(result).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/exec.js
new file mode 100644
index 000000000000..9622d3c06339
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/exec.js
@@ -0,0 +1,14 @@
+function triple (x) {
+  return x * 3
+}
+
+async function asyncFunction(n) {
+  return n
+    |> Math.abs(^^)
+    |> await Promise.resolve(^^)
+    |> triple(^^);
+}
+
+asyncFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/input.js
new file mode 100644
index 000000000000..9622d3c06339
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/input.js
@@ -0,0 +1,14 @@
+function triple (x) {
+  return x * 3
+}
+
+async function asyncFunction(n) {
+  return n
+    |> Math.abs(^^)
+    |> await Promise.resolve(^^)
+    |> triple(^^);
+}
+
+asyncFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/options.json
new file mode 100644
index 000000000000..f19c36b8eef1
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/options.json
@@ -0,0 +1,6 @@
+{
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  },
+  "minNodeVersion": "8.0.0"
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/output.js
new file mode 100644
index 000000000000..aa3d4e62d419
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-await/output.js
@@ -0,0 +1,13 @@
+function triple(x) {
+  return x * 3;
+}
+
+async function asyncFunction(n) {
+  var _ref, _ref2, _ref3;
+
+  return _ref3 = n, (_ref2 = Math.abs(_ref3), (_ref = await Promise.resolve(_ref2), triple(_ref)));
+}
+
+asyncFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/exec.js
new file mode 100644
index 000000000000..e2477d250ce1
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/exec.js
@@ -0,0 +1,20 @@
+const result = 1
+ |> class {
+    #baz;
+
+    constructor () {
+      this.#baz = ^^;
+    }
+
+    #bar () {
+      return this.#baz + 2;
+    }
+
+    foo () {
+      return this.#bar() + 3;
+    }
+ }
+ |> new ^^
+ |> ^^.foo();
+
+expect(result).toBe(1 + 2 + 3);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/input.js
new file mode 100644
index 000000000000..e2477d250ce1
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/input.js
@@ -0,0 +1,20 @@
+const result = 1
+ |> class {
+    #baz;
+
+    constructor () {
+      this.#baz = ^^;
+    }
+
+    #bar () {
+      return this.#baz + 2;
+    }
+
+    foo () {
+      return this.#bar() + 3;
+    }
+ }
+ |> new ^^
+ |> ^^.foo();
+
+expect(result).toBe(1 + 2 + 3);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/options.json
new file mode 100644
index 000000000000..470ca4a32b9b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "^^" }]
+  ],
+  "minNodeVersion": "14.0.0"
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/output.js
new file mode 100644
index 000000000000..638f9cda750f
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-class-expression-and-private-properties/output.js
@@ -0,0 +1,19 @@
+var _ref, _ref2, _ref3;
+
+const result = (_ref3 = 1, (_ref2 = class {
+  #baz;
+
+  constructor() {
+    this.#baz = _ref3;
+  }
+
+  #bar() {
+    return this.#baz + 2;
+  }
+
+  foo() {
+    return this.#bar() + 3;
+  }
+
+}, (_ref = new _ref2(), _ref.foo())));
+expect(result).toBe(1 + 2 + 3);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/exec.js
new file mode 100644
index 000000000000..de3a6fc8defa
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/exec.js
@@ -0,0 +1,4 @@
+const program = '(function() { return this; })()';
+const result = program |> eval(^^);
+
+expect(result).not.toBeUndefined();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/input.js
new file mode 100644
index 000000000000..de3a6fc8defa
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/input.js
@@ -0,0 +1,4 @@
+const program = '(function() { return this; })()';
+const result = program |> eval(^^);
+
+expect(result).not.toBeUndefined();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/output.js
new file mode 100644
index 000000000000..c5dbd6107a44
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-eval/output.js
@@ -0,0 +1,5 @@
+var _ref;
+
+const program = '(function() { return this; })()';
+const result = (_ref = program, eval(_ref));
+expect(result).not.toBeUndefined();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/exec.js
new file mode 100644
index 000000000000..0975847bc287
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/exec.js
@@ -0,0 +1,7 @@
+const result = 5
+  |> Math.pow(^^, 2)
+  |> (^^ + 1
+    |> `${^^} apples`
+    |> ^^.toUpperCase());
+
+expect(result).toEqual('26 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/input.js
new file mode 100644
index 000000000000..0975847bc287
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/input.js
@@ -0,0 +1,7 @@
+const result = 5
+  |> Math.pow(^^, 2)
+  |> (^^ + 1
+    |> `${^^} apples`
+    |> ^^.toUpperCase());
+
+expect(result).toEqual('26 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/output.js
new file mode 100644
index 000000000000..8ee6b4bbf42f
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-nested-pipe/output.js
@@ -0,0 +1,4 @@
+var _ref, _ref2, _ref3, _ref4;
+
+const result = (_ref4 = 5, (_ref3 = Math.pow(_ref4, 2), (_ref2 = _ref3 + 1, (_ref = `${_ref2} apples`, _ref.toUpperCase()))));
+expect(result).toEqual('26 APPLES');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/exec.js
new file mode 100644
index 000000000000..c9a4ae8080e6
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/exec.js
@@ -0,0 +1,10 @@
+function area(rect) {
+  return rect.width * rect.height;
+}
+
+const result = -5
+  |> Math.abs(^^)
+  |> { width: ^^, height: ^^ + 3 }
+  |> area(^^);
+
+expect(result).toBe(40);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/input.js
new file mode 100644
index 000000000000..c9a4ae8080e6
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/input.js
@@ -0,0 +1,10 @@
+function area(rect) {
+  return rect.width * rect.height;
+}
+
+const result = -5
+  |> Math.abs(^^)
+  |> { width: ^^, height: ^^ + 3 }
+  |> area(^^);
+
+expect(result).toBe(40);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/output.js
new file mode 100644
index 000000000000..cd74f2422e0a
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-object-literal/output.js
@@ -0,0 +1,11 @@
+var _ref, _ref2, _ref3;
+
+function area(rect) {
+  return rect.width * rect.height;
+}
+
+const result = (_ref3 = -5, (_ref2 = Math.abs(_ref3), (_ref = {
+  width: _ref2,
+  height: _ref2 + 3
+}, area(_ref))));
+expect(result).toBe(40);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/exec.js
new file mode 100644
index 000000000000..7d906adffb42
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/exec.js
@@ -0,0 +1,3 @@
+const result = 'Hello' |> ^^.toUpperCase();
+
+expect(result).toBe('HELLO');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/input.js
new file mode 100644
index 000000000000..7d906adffb42
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/input.js
@@ -0,0 +1,3 @@
+const result = 'Hello' |> ^^.toUpperCase();
+
+expect(result).toBe('HELLO');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/output.js
new file mode 100644
index 000000000000..029efa564267
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-topic-method-call/output.js
@@ -0,0 +1,4 @@
+var _ref;
+
+const result = (_ref = 'Hello', _ref.toUpperCase());
+expect(result).toBe('HELLO');
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/exec.js
new file mode 100644
index 000000000000..0e65723ffaaf
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/exec.js
@@ -0,0 +1,13 @@
+function *myGenerator(n) {
+  return n
+  |> (yield ^^)
+  |> Math.abs(^^);
+}
+
+const myIterator = myGenerator(15);
+
+const yieldedValue = myIterator.next().value;
+const returnedValue = myIterator.next(-30).value;
+
+expect(yieldedValue).toBe(15);
+expect(returnedValue).toBe(30);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/input.js
new file mode 100644
index 000000000000..0e65723ffaaf
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/input.js
@@ -0,0 +1,13 @@
+function *myGenerator(n) {
+  return n
+  |> (yield ^^)
+  |> Math.abs(^^);
+}
+
+const myIterator = myGenerator(15);
+
+const yieldedValue = myIterator.next().value;
+const returnedValue = myIterator.next(-30).value;
+
+expect(yieldedValue).toBe(15);
+expect(returnedValue).toBe(30);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/output.js
new file mode 100644
index 000000000000..40f127c27ae2
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-body-with-yield/output.js
@@ -0,0 +1,11 @@
+function* myGenerator(n) {
+  var _ref, _ref2;
+
+  return _ref2 = n, (_ref = yield _ref2, Math.abs(_ref));
+}
+
+const myIterator = myGenerator(15);
+const yieldedValue = myIterator.next().value;
+const returnedValue = myIterator.next(-30).value;
+expect(yieldedValue).toBe(15);
+expect(returnedValue).toBe(30);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/exec.js
new file mode 100644
index 000000000000..9c09ad685c5d
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/exec.js
@@ -0,0 +1,3 @@
+const result = (5 |> Math.pow(^^, 2)) |> ^^ + 1;
+
+expect(result).toEqual(26);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/input.js
new file mode 100644
index 000000000000..9c09ad685c5d
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/input.js
@@ -0,0 +1,3 @@
+const result = (5 |> Math.pow(^^, 2)) |> ^^ + 1;
+
+expect(result).toEqual(26);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/output.js
new file mode 100644
index 000000000000..1adde6582021
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-head-with-nested-pipe/output.js
@@ -0,0 +1,4 @@
+var _ref, _ref2;
+
+const result = (_ref2 = (_ref = 5, Math.pow(_ref, 2)), _ref2 + 1);
+expect(result).toEqual(26);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/exec.js
new file mode 100644
index 000000000000..a7652bd33860
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/exec.js
@@ -0,0 +1,6 @@
+const result = () => -2.2 // -2.2
+  |> Math.floor(^^) // -3
+  |> (() => Math.pow(^^, 5)) // () => -243
+  |> ^^(); // -243
+
+expect(result()).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/input.js
new file mode 100644
index 000000000000..a7652bd33860
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/input.js
@@ -0,0 +1,6 @@
+const result = () => -2.2 // -2.2
+  |> Math.floor(^^) // -3
+  |> (() => Math.pow(^^, 5)) // () => -243
+  |> ^^(); // -243
+
+expect(result()).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/output.js
new file mode 100644
index 000000000000..66106a985d16
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/pipe-in-arrow-function/output.js
@@ -0,0 +1,11 @@
+const result = () => {
+  var _ref, _ref2, _ref3;
+
+  return _ref3 = -2.2 // -2.2
+  , (_ref2 = Math.floor(_ref3) // -3
+  , (_ref = () => Math.pow(_ref2, 5) // () => -243
+  , _ref()));
+}; // -243
+
+
+expect(result()).toBe(-243);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/exec.js
new file mode 100644
index 000000000000..49d1e40d10cb
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/exec.js
@@ -0,0 +1,5 @@
+const triple = x => x * 3;
+
+const result = -7 |> Math.abs(^^) |> triple(^^);
+
+return expect(result).toBe(21);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/input.js
new file mode 100644
index 000000000000..49d1e40d10cb
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/input.js
@@ -0,0 +1,5 @@
+const triple = x => x * 3;
+
+const result = -7 |> Math.abs(^^) |> triple(^^);
+
+return expect(result).toBe(21);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/options.json
new file mode 100644
index 000000000000..3149096b66a1
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/options.json
@@ -0,0 +1,9 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "^^" }],
+    "transform-arrow-functions"
+  ],
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  }
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/output.js
new file mode 100644
index 000000000000..23cdd3fe2a2b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-arrow-functions/output.js
@@ -0,0 +1,8 @@
+var _ref, _ref2;
+
+const triple = function (x) {
+  return x * 3;
+};
+
+const result = (_ref2 = -7, (_ref = Math.abs(_ref2), triple(_ref)));
+return expect(result).toBe(21);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/exec.js
new file mode 100644
index 000000000000..806b90404de2
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/exec.js
@@ -0,0 +1,13 @@
+const triple = (x) => x * 3;
+
+async function myFunction(n) {
+  return n
+    |> Math.abs(^^)
+    |> Promise.resolve(^^)
+    |> await ^^
+    |> triple(^^);
+}
+
+return myFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/input.js
new file mode 100644
index 000000000000..806b90404de2
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/input.js
@@ -0,0 +1,13 @@
+const triple = (x) => x * 3;
+
+async function myFunction(n) {
+  return n
+    |> Math.abs(^^)
+    |> Promise.resolve(^^)
+    |> await ^^
+    |> triple(^^);
+}
+
+return myFunction(-7).then(result => {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/options.json
new file mode 100644
index 000000000000..63e28b169e60
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/options.json
@@ -0,0 +1,10 @@
+{
+  "plugins": [
+    ["proposal-pipeline-operator", { "proposal": "hack", "topicToken": "^^" }],
+    "transform-arrow-functions"
+  ],
+  "parserOpts": {
+    "allowReturnOutsideFunction": true
+  },
+  "minNodeVersion": "8.0.0"
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/output.js
new file mode 100644
index 000000000000..3a32f6e23831
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/transform-await-and-arrow-functions/output.js
@@ -0,0 +1,13 @@
+const triple = function (x) {
+  return x * 3;
+};
+
+async function myFunction(n) {
+  var _ref, _ref2, _ref3, _ref4;
+
+  return _ref4 = n, (_ref3 = Math.abs(_ref4), (_ref2 = Promise.resolve(_ref3), (_ref = await _ref2, triple(_ref))));
+}
+
+return myFunction(-7).then(function (result) {
+  expect(result).toBe(21);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/exec.js
new file mode 100644
index 000000000000..931b5fb0b577
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/exec.js
@@ -0,0 +1,7 @@
+let i = 0;
+let sum = 0;
+
+while (i |> (i = ^^ + 1) |> ^^ <= 10)
+  sum += i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/input.js
new file mode 100644
index 000000000000..931b5fb0b577
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/input.js
@@ -0,0 +1,7 @@
+let i = 0;
+let sum = 0;
+
+while (i |> (i = ^^ + 1) |> ^^ <= 10)
+  sum += i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/output.js
new file mode 100644
index 000000000000..0622dfee4902
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/while-statement-with-pipe-in-condition/output.js
@@ -0,0 +1,10 @@
+let i = 0;
+let sum = 0;
+
+while (_ref2 = i, (_ref = i = _ref2 + 1, _ref <= 10)) {
+  var _ref, _ref2;
+
+  sum += i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/exec.js
new file mode 100644
index 000000000000..49ac297fbbd7
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/exec.js
@@ -0,0 +1,3 @@
+const x = 0 |> ^^ + 1;
+
+expect(x).toBe(1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/input.js
new file mode 100644
index 000000000000..49ac297fbbd7
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/input.js
@@ -0,0 +1,3 @@
+const x = 0 |> ^^ + 1;
+
+expect(x).toBe(1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/output.js
new file mode 100644
index 000000000000..5ca2ce9e5390
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-assignment/output.js
@@ -0,0 +1,4 @@
+var _ref;
+
+const x = (_ref = 0, _ref + 1);
+expect(x).toBe(1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/exec.js
new file mode 100644
index 000000000000..d8eca0034388
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/exec.js
@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0 |> ^^; i <= 10; i++)
+  sum += i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/input.js
new file mode 100644
index 000000000000..d8eca0034388
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/input.js
@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0 |> ^^; i <= 10; i++)
+  sum += i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/output.js
new file mode 100644
index 000000000000..dd399138c6fb
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-init/output.js
@@ -0,0 +1,9 @@
+let sum = 0;
+
+for (var i = (_ref = 0, _ref); i <= 10; i++) {
+  var _ref;
+
+  sum += i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/exec.js
new file mode 100644
index 000000000000..1c3a2949330b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/exec.js
@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0; i |> ^^ <= 10; i++)
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/input.js
new file mode 100644
index 000000000000..1c3a2949330b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/input.js
@@ -0,0 +1,5 @@
+let sum = 0;
+for (var i = 0; i |> ^^ <= 10; i++)
+  sum = sum + i;
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/output.js
new file mode 100644
index 000000000000..14ae06d74abf
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-test/output.js
@@ -0,0 +1,9 @@
+let sum = 0;
+
+for (var i = 0; _ref = i, _ref <= 10; i++) {
+  var _ref;
+
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/exec.js
new file mode 100644
index 000000000000..4a4f210bad58
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/exec.js
@@ -0,0 +1,6 @@
+let sum = 0;
+for (var i = 0; i <= 10; i = i |> ^^ + 1) {
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/input.js
new file mode 100644
index 000000000000..4a4f210bad58
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/input.js
@@ -0,0 +1,6 @@
+let sum = 0;
+for (var i = 0; i <= 10; i = i |> ^^ + 1) {
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1)
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/output.js
new file mode 100644
index 000000000000..a741096b130d
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-for-classic-statement-update/output.js
@@ -0,0 +1,9 @@
+let sum = 0;
+
+for (var i = 0; i <= 10; i = (_ref = i, _ref + 1)) {
+  var _ref;
+
+  sum = sum + i;
+}
+
+expect(sum).toBe(10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-generator-with-yield/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-generator-with-yield/input.js
new file mode 100644
index 000000000000..18d48528ed79
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-generator-with-yield/input.js
@@ -0,0 +1,5 @@
+function * myGenerator(n) {
+  return n
+    |> (yield ^^)
+    |> Math.abs(^^);
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-generator-with-yield/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-generator-with-yield/output.js
new file mode 100644
index 000000000000..4e9cfe3a1240
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-generator-with-yield/output.js
@@ -0,0 +1,5 @@
+function* myGenerator(n) {
+  var _ref, _ref2;
+
+  return _ref2 = n, (_ref = yield _ref2, Math.abs(_ref));
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-if-else-block/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-if-else-block/input.js
new file mode 100644
index 000000000000..b9b1692c7123
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-if-else-block/input.js
@@ -0,0 +1,4 @@
+if (v |> e(^^) |> f(^^))
+  g() |> h(^^, ^^ + 1) |> i(^^);
+else
+  j();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-if-else-block/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-if-else-block/output.js
new file mode 100644
index 000000000000..5d542dc97ffc
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-if-else-block/output.js
@@ -0,0 +1,3 @@
+var _ref, _ref2, _ref3, _ref4;
+
+if (_ref2 = v, (_ref = e(_ref2), f(_ref))) _ref4 = g(), (_ref3 = h(_ref4, _ref4 + 1), i(_ref3));else j();
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/exec.js
new file mode 100644
index 000000000000..26837dd5150f
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/exec.js
@@ -0,0 +1,3 @@
+var i = 0;
+
+expect(i).toBe(0);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/input.js
new file mode 100644
index 000000000000..26837dd5150f
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/input.js
@@ -0,0 +1,3 @@
+var i = 0;
+
+expect(i).toBe(0);
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/output.js
new file mode 100644
index 000000000000..126fd403042b
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/hack-double-caret/within-var-statement/output.js
@@ -0,0 +1,2 @@
+var i = 0;
+expect(i).toBe(0);
diff --git a/packages/babel-plugin-syntax-pipeline-operator/src/index.ts b/packages/babel-plugin-syntax-pipeline-operator/src/index.ts
index 6ee8d1fbb638..4a9013ed8965 100644
--- a/packages/babel-plugin-syntax-pipeline-operator/src/index.ts
+++ b/packages/babel-plugin-syntax-pipeline-operator/src/index.ts
@@ -1,7 +1,7 @@
 import { declare } from "@babel/helper-plugin-utils";
 
 const PIPELINE_PROPOSALS = ["minimal", "fsharp", "hack", "smart"];
-const TOPIC_TOKENS = ["^", "%", "#"];
+const TOPIC_TOKENS = ["^^", "@@", "^", "%", "#"];
 const documentationURL =
   "https://babeljs.io/docs/en/babel-plugin-proposal-pipeline-operator";