From d074a79cbd71e52e39ce12e15ec2d98c69d3587d Mon Sep 17 00:00:00 2001
From: Andrew Branch <andrew@wheream.io>
Date: Mon, 9 May 2022 18:40:24 +0000
Subject: [PATCH] Cherry-pick PR #49035 into release-4.7

Component commits:
e8df495a1a Fix module specifier generation crash from typesVersions
---
 src/compiler/moduleSpecifiers.ts              |  1 +
 .../importNameCodeFix_typesVersions.ts        | 34 +++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 tests/cases/fourslash/importNameCodeFix_typesVersions.ts

diff --git a/src/compiler/moduleSpecifiers.ts b/src/compiler/moduleSpecifiers.ts
index ed8d9f90b0ae2..44d20c9ff59ef 100644
--- a/src/compiler/moduleSpecifiers.ts
+++ b/src/compiler/moduleSpecifiers.ts
@@ -810,6 +810,7 @@ namespace ts.moduleSpecifiers {
     function removeExtensionAndIndexPostFix(fileName: string, ending: Ending, options: CompilerOptions, host?: ModuleSpecifierResolutionHost): string {
         if (fileExtensionIsOneOf(fileName, [Extension.Json, Extension.Mjs, Extension.Cjs])) return fileName;
         const noExtension = removeFileExtension(fileName);
+        if (fileName === noExtension) return fileName;
         if (fileExtensionIsOneOf(fileName, [Extension.Dmts, Extension.Mts, Extension.Dcts, Extension.Cts])) return noExtension + getJSExtensionForFile(fileName, options);
         switch (ending) {
             case Ending.Minimal:
diff --git a/tests/cases/fourslash/importNameCodeFix_typesVersions.ts b/tests/cases/fourslash/importNameCodeFix_typesVersions.ts
new file mode 100644
index 0000000000000..9f69e3eb44f8d
--- /dev/null
+++ b/tests/cases/fourslash/importNameCodeFix_typesVersions.ts
@@ -0,0 +1,34 @@
+/// <reference path="fourslash.ts" />
+
+// @module: commonjs
+// @checkJs: true
+
+// @Filename: /node_modules/unified/package.json
+//// {
+////   "name": "unified",
+////   "types": "types/ts3.4/index.d.ts",
+////   "typesVersions": {
+////     ">=4.0": {
+////       "types/ts3.4/*": [
+////         "types/ts4.0/*"
+////       ]
+////     }
+////   }
+//// }
+
+// @Filename: /node_modules/unified/types/ts3.4/index.d.ts
+//// export declare const x: number;
+
+// @Filename: /node_modules/unified/types/ts4.0/index.d.ts
+//// export declare const x: number;
+
+// @Filename: /foo.js
+//// import {} from "unified";
+
+// @Filename: /index.js
+//// x/**/
+
+verify.importFixModuleSpecifiers("", [
+  "unified",
+  "unified/types/ts3.4/", // TODO: this is wrong #49034
+], { importModuleSpecifierEnding: "js" });