🤖 Pick PR #53599 (Ignore allowImportingTsExtensions...) into release-5.0 (#53600)

Co-authored-by: Andrew Branch <andrew@wheream.io>

Author: TypeScript Bot

src/compiler/commandLineParser.ts

@@ -1104,6 +1104,7 @@ const commandOptionsWithoutBuild: CommandLineOption[] = [
         category: Diagnostics.Modules,
         description: Diagnostics.Allow_imports_to_include_TypeScript_file_extensions_Requires_moduleResolution_bundler_and_either_noEmit_or_emitDeclarationOnly_to_be_set,
         defaultValueDescription: false,
+        transpileOptionValue: undefined,
     },
     {
         name: "resolvePackageJsonExports",

src/testRunner/unittests/services/transpile.ts

@@ -606,4 +606,18 @@ export * as alias from './file';`, {
             testVerbatimModuleSyntax: "only"
         }
     );
+
+    transpilesCorrectly("Can transpile .ts extensions without error",
+        `import { foo } from "./foo.ts";`, {
+            options: { compilerOptions: { module: ts.ModuleKind.ESNext, target: ts.ScriptTarget.ESNext } },
+            testVerbatimModuleSyntax: true
+        }
+    );
+
+    transpilesCorrectly("Ignores `allowImportingTsExtensions` without `noEmit` error",
+        `import { foo } from "./foo.ts";`, {
+            options: { compilerOptions: { module: ts.ModuleKind.ESNext, allowImportingTsExtensions: true, target: ts.ScriptTarget.ESNext } },
+            testVerbatimModuleSyntax: true
+        }
+    );
 });