From 13a1cfd396e6c1f1735c546b3bc4196f69bc52d1 Mon Sep 17 00:00:00 2001
From: Brian Ng <bng412@gmail.com>
Date: Sun, 11 Oct 2020 06:03:57 -0500
Subject: [PATCH] Move check for TSTypeCastExpression to catch another case
 (#12161)

---
 .../src/plugins/typescript/index.js           | 35 ++++++-----
 .../cast/parameter-typecast/input.ts          |  1 +
 .../cast/parameter-typecast/output.json       | 59 ++++++++++++++++++-
 3 files changed, 78 insertions(+), 17 deletions(-)

diff --git a/packages/babel-parser/src/plugins/typescript/index.js b/packages/babel-parser/src/plugins/typescript/index.js
index 1b9b7f1f3e83..58427987d33c 100644
--- a/packages/babel-parser/src/plugins/typescript/index.js
+++ b/packages/babel-parser/src/plugins/typescript/index.js
@@ -1803,6 +1803,27 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
     }
 
+    parseExprListItem(
+      allowEmpty: ?boolean,
+      refExpressionErrors?: ?ExpressionErrors,
+      refNeedsArrowPos: ?Pos,
+      allowPlaceholder: ?boolean,
+    ): ?N.Expression {
+      const node = super.parseExprListItem(
+        allowEmpty,
+        refExpressionErrors,
+        refNeedsArrowPos,
+        allowPlaceholder,
+      );
+
+      // Handle `func(a: T)` or `func<T>(a: T)`
+      if (!refNeedsArrowPos && node?.type === "TSTypeCastExpression") {
+        this.raise(node.start, TSErrors.UnexpectedTypeAnnotation);
+      }
+
+      return node;
+    }
+
     parseSubscript(
       base: N.Expression,
       startPos: number,
@@ -2725,20 +2746,6 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       return node.expression;
     }
 
-    toReferencedList(
-      exprList: $ReadOnlyArray<?N.Expression>,
-      isInParens?: boolean, // eslint-disable-line no-unused-vars
-    ): $ReadOnlyArray<?N.Expression> {
-      for (let i = 0; i < exprList.length; i++) {
-        const expr = exprList[i];
-        if (expr?.type === "TSTypeCastExpression") {
-          this.raise(expr.start, TSErrors.UnexpectedTypeAnnotation);
-        }
-      }
-
-      return exprList;
-    }
-
     shouldParseArrow() {
       return this.match(tt.colon) || super.shouldParseArrow();
     }
diff --git a/packages/babel-parser/test/fixtures/typescript/cast/parameter-typecast/input.ts b/packages/babel-parser/test/fixtures/typescript/cast/parameter-typecast/input.ts
index c494cc00bc39..0a26da3585bc 100644
--- a/packages/babel-parser/test/fixtures/typescript/cast/parameter-typecast/input.ts
+++ b/packages/babel-parser/test/fixtures/typescript/cast/parameter-typecast/input.ts
@@ -1 +1,2 @@
 func(a: T);
+func<T>(a: T);
diff --git a/packages/babel-parser/test/fixtures/typescript/cast/parameter-typecast/output.json b/packages/babel-parser/test/fixtures/typescript/cast/parameter-typecast/output.json
index 1ed571551016..d9518e74b169 100644
--- a/packages/babel-parser/test/fixtures/typescript/cast/parameter-typecast/output.json
+++ b/packages/babel-parser/test/fixtures/typescript/cast/parameter-typecast/output.json
@@ -1,12 +1,13 @@
 {
   "type": "File",
-  "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+  "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":14}},
   "errors": [
-    "SyntaxError: Did not expect a type annotation here. (1:5)"
+    "SyntaxError: Did not expect a type annotation here. (1:5)",
+    "SyntaxError: Did not expect a type annotation here. (2:8)"
   ],
   "program": {
     "type": "Program",
-    "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+    "start":0,"end":26,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":14}},
     "sourceType": "module",
     "interpreter": null,
     "body": [
@@ -46,6 +47,58 @@
             }
           ]
         }
+      },
+      {
+        "type": "ExpressionStatement",
+        "start":12,"end":26,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":14}},
+        "expression": {
+          "type": "CallExpression",
+          "start":12,"end":25,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":13}},
+          "callee": {
+            "type": "Identifier",
+            "start":12,"end":16,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":4},"identifierName":"func"},
+            "name": "func"
+          },
+          "arguments": [
+            {
+              "type": "TSTypeCastExpression",
+              "start":20,"end":24,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":12}},
+              "expression": {
+                "type": "Identifier",
+                "start":20,"end":21,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":9},"identifierName":"a"},
+                "name": "a"
+              },
+              "typeAnnotation": {
+                "type": "TSTypeAnnotation",
+                "start":21,"end":24,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":12}},
+                "typeAnnotation": {
+                  "type": "TSTypeReference",
+                  "start":23,"end":24,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":12}},
+                  "typeName": {
+                    "type": "Identifier",
+                    "start":23,"end":24,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":12},"identifierName":"T"},
+                    "name": "T"
+                  }
+                }
+              }
+            }
+          ],
+          "typeParameters": {
+            "type": "TSTypeParameterInstantiation",
+            "start":16,"end":19,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":7}},
+            "params": [
+              {
+                "type": "TSTypeReference",
+                "start":17,"end":18,"loc":{"start":{"line":2,"column":5},"end":{"line":2,"column":6}},
+                "typeName": {
+                  "type": "Identifier",
+                  "start":17,"end":18,"loc":{"start":{"line":2,"column":5},"end":{"line":2,"column":6},"identifierName":"T"},
+                  "name": "T"
+                }
+              }
+            ]
+          }
+        }
       }
     ],
     "directives": []