Remove always-incorrect error message about importing .ts extensions

src/compiler/checker.ts

@@ -4961,14 +4961,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 error(errorNode, resolutionDiagnostic, moduleReference, resolvedModule.resolvedFileName);
             }
             else {
-                const tsExtension = tryExtractTSExtension(moduleReference);
                 const isExtensionlessRelativePathImport = pathIsRelative(moduleReference) && !hasExtension(moduleReference);
                 const resolutionIsNode16OrNext = moduleResolutionKind === ModuleResolutionKind.Node16 ||
                     moduleResolutionKind === ModuleResolutionKind.NodeNext;
-                if (tsExtension) {
-                    errorOnTSExtensionImport(tsExtension);
-                }
-                else if (!getResolveJsonModule(compilerOptions) &&
+                if (!getResolveJsonModule(compilerOptions) &&
                     fileExtensionIs(moduleReference, Extension.Json) &&
                     moduleResolutionKind !== ModuleResolutionKind.Classic &&
                     hasJsonModuleEmitEnabled(compilerOptions)) {
@@ -4993,11 +4989,6 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         }
         return undefined;
 
-        function errorOnTSExtensionImport(tsExtension: string) {
-            const diag = Diagnostics.An_import_path_cannot_end_with_a_0_extension_Consider_importing_1_instead;
-            error(errorNode, diag, tsExtension, getSuggestedImportSource(tsExtension));
-        }
-
         function getSuggestedImportSource(tsExtension: string) {
             const importSourceWithoutExtension = removeExtension(moduleReference, tsExtension);
             /**

src/compiler/diagnosticMessages.json

@@ -3026,10 +3026,6 @@
         "category": "Error",
         "code": 2690
     },
-    "An import path cannot end with a '{0}' extension. Consider importing '{1}' instead.": {
-        "category": "Error",
-        "code": 2691
-    },
     "'{0}' is a primitive, but '{1}' is a wrapper object. Prefer using '{0}' when possible.": {
         "category": "Error",
         "code": 2692

tests/baselines/reference/allowImportingTsExtensions(moduleresolution=bundler).errors.txt

@@ -0,0 +1,32 @@
+/c.ts(1,16): error TS2307: Cannot find module './thisfiledoesnotexist.ts' or its corresponding type declarations.
+
+
+==== /ts.ts (0 errors) ====
+    export {};
+
+==== /tsx.tsx (0 errors) ====
+    export {};
+
+==== /dts.d.ts (0 errors) ====
+    export {};
+
+==== /b.ts (0 errors) ====
+    import {} from "./ts.js";
+    import {} from "./ts.ts";
+    import type {} from "./ts.d.ts";
+
+    import {} from "./tsx.js";
+    import {} from "./tsx.jsx";
+    import {} from "./tsx.ts";
+    import {} from "./tsx.tsx";
+    import type {} from "./tsx.d.ts";
+
+    import {} from "./dts.js";
+    import {} from "./dts.ts";
+    import type {} from "./dts.d.ts";
+
+==== /c.ts (1 errors) ====
+    import {} from "./thisfiledoesnotexist.ts";
+                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './thisfiledoesnotexist.ts' or its corresponding type declarations.
+

tests/baselines/reference/allowImportingTsExtensions(moduleresolution=classic).errors.txt

@@ -0,0 +1,32 @@
+/c.ts(1,16): error TS2792: Cannot find module './thisfiledoesnotexist.ts'. Did you mean to set the 'moduleResolution' option to 'nodenext', or to add aliases to the 'paths' option?
+
+
+==== /ts.ts (0 errors) ====
+    export {};
+
+==== /tsx.tsx (0 errors) ====
+    export {};
+
+==== /dts.d.ts (0 errors) ====
+    export {};
+
+==== /b.ts (0 errors) ====
+    import {} from "./ts.js";
+    import {} from "./ts.ts";
+    import type {} from "./ts.d.ts";
+
+    import {} from "./tsx.js";
+    import {} from "./tsx.jsx";
+    import {} from "./tsx.ts";
+    import {} from "./tsx.tsx";
+    import type {} from "./tsx.d.ts";
+
+    import {} from "./dts.js";
+    import {} from "./dts.ts";
+    import type {} from "./dts.d.ts";
+
+==== /c.ts (1 errors) ====
+    import {} from "./thisfiledoesnotexist.ts";
+                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2792: Cannot find module './thisfiledoesnotexist.ts'. Did you mean to set the 'moduleResolution' option to 'nodenext', or to add aliases to the 'paths' option?
+

tests/baselines/reference/allowImportingTsExtensions(moduleresolution=node10).errors.txt

@@ -0,0 +1,32 @@
+/c.ts(1,16): error TS2307: Cannot find module './thisfiledoesnotexist.ts' or its corresponding type declarations.
+
+
+==== /ts.ts (0 errors) ====
+    export {};
+
+==== /tsx.tsx (0 errors) ====
+    export {};
+
+==== /dts.d.ts (0 errors) ====
+    export {};
+
+==== /b.ts (0 errors) ====
+    import {} from "./ts.js";
+    import {} from "./ts.ts";
+    import type {} from "./ts.d.ts";
+
+    import {} from "./tsx.js";
+    import {} from "./tsx.jsx";
+    import {} from "./tsx.ts";
+    import {} from "./tsx.tsx";
+    import type {} from "./tsx.d.ts";
+
+    import {} from "./dts.js";
+    import {} from "./dts.ts";
+    import type {} from "./dts.d.ts";
+
+==== /c.ts (1 errors) ====
+    import {} from "./thisfiledoesnotexist.ts";
+                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './thisfiledoesnotexist.ts' or its corresponding type declarations.
+

tests/baselines/reference/allowImportingTsExtensions(moduleresolution=node16).errors.txt

@@ -0,0 +1,32 @@
+/c.ts(1,16): error TS2307: Cannot find module './thisfiledoesnotexist.ts' or its corresponding type declarations.
+
+
+==== /ts.ts (0 errors) ====
+    export {};
+
+==== /tsx.tsx (0 errors) ====
+    export {};
+
+==== /dts.d.ts (0 errors) ====
+    export {};
+
+==== /b.ts (0 errors) ====
+    import {} from "./ts.js";
+    import {} from "./ts.ts";
+    import type {} from "./ts.d.ts";
+
+    import {} from "./tsx.js";
+    import {} from "./tsx.jsx";
+    import {} from "./tsx.ts";
+    import {} from "./tsx.tsx";
+    import type {} from "./tsx.d.ts";
+
+    import {} from "./dts.js";
+    import {} from "./dts.ts";
+    import type {} from "./dts.d.ts";
+
+==== /c.ts (1 errors) ====
+    import {} from "./thisfiledoesnotexist.ts";
+                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './thisfiledoesnotexist.ts' or its corresponding type declarations.
+

tests/baselines/reference/allowImportingTsExtensions(moduleresolution=nodenext).errors.txt

@@ -0,0 +1,32 @@
+/c.ts(1,16): error TS2307: Cannot find module './thisfiledoesnotexist.ts' or its corresponding type declarations.
+
+
+==== /ts.ts (0 errors) ====
+    export {};
+
+==== /tsx.tsx (0 errors) ====
+    export {};
+
+==== /dts.d.ts (0 errors) ====
+    export {};
+
+==== /b.ts (0 errors) ====
+    import {} from "./ts.js";
+    import {} from "./ts.ts";
+    import type {} from "./ts.d.ts";
+
+    import {} from "./tsx.js";
+    import {} from "./tsx.jsx";
+    import {} from "./tsx.ts";
+    import {} from "./tsx.tsx";
+    import type {} from "./tsx.d.ts";
+
+    import {} from "./dts.js";
+    import {} from "./dts.ts";
+    import type {} from "./dts.d.ts";
+
+==== /c.ts (1 errors) ====
+    import {} from "./thisfiledoesnotexist.ts";
+                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2307: Cannot find module './thisfiledoesnotexist.ts' or its corresponding type declarations.
+

tests/baselines/reference/declarationFileForTsJsImport.errors.txt

@@ -1,15 +1,15 @@
 tests/cases/conformance/nonjsExtensions/main.ts(1,18): error TS2307: Cannot find module './file.js' or its corresponding type declarations.
 tests/cases/conformance/nonjsExtensions/main.ts(2,18): error TS2307: Cannot find module './file.jsx' or its corresponding type declarations.
-tests/cases/conformance/nonjsExtensions/main.ts(3,18): error TS2691: An import path cannot end with a '.ts' extension. Consider importing './file.js' instead.
-tests/cases/conformance/nonjsExtensions/main.ts(4,18): error TS2691: An import path cannot end with a '.tsx' extension. Consider importing './file.js' instead.
+tests/cases/conformance/nonjsExtensions/main.ts(3,18): error TS2307: Cannot find module './file.ts' or its corresponding type declarations.
+tests/cases/conformance/nonjsExtensions/main.ts(4,18): error TS2307: Cannot find module './file.tsx' or its corresponding type declarations.
 tests/cases/conformance/nonjsExtensions/main.ts(5,18): error TS2307: Cannot find module './file.mjs' or its corresponding type declarations.
 tests/cases/conformance/nonjsExtensions/main.ts(6,18): error TS2307: Cannot find module './file.cjs' or its corresponding type declarations.
-tests/cases/conformance/nonjsExtensions/main.ts(7,18): error TS2691: An import path cannot end with a '.mts' extension. Consider importing './file.mjs' instead.
-tests/cases/conformance/nonjsExtensions/main.ts(8,18): error TS2691: An import path cannot end with a '.cts' extension. Consider importing './file.cjs' instead.
-tests/cases/conformance/nonjsExtensions/main.ts(9,18): error TS2691: An import path cannot end with a '.d.ts' extension. Consider importing './file.js' instead.
-tests/cases/conformance/nonjsExtensions/main.ts(10,19): error TS2691: An import path cannot end with a '.d.cts' extension. Consider importing './file.js' instead.
-tests/cases/conformance/nonjsExtensions/main.ts(11,19): error TS2691: An import path cannot end with a '.d.mts' extension. Consider importing './file.js' instead.
-tests/cases/conformance/nonjsExtensions/main.ts(12,19): error TS2691: An import path cannot end with a '.ts' extension. Consider importing './file.d.json.js' instead.
+tests/cases/conformance/nonjsExtensions/main.ts(7,18): error TS2307: Cannot find module './file.mts' or its corresponding type declarations.
+tests/cases/conformance/nonjsExtensions/main.ts(8,18): error TS2307: Cannot find module './file.cts' or its corresponding type declarations.
+tests/cases/conformance/nonjsExtensions/main.ts(9,18): error TS2307: Cannot find module './file.d.ts' or its corresponding type declarations.
+tests/cases/conformance/nonjsExtensions/main.ts(10,19): error TS2307: Cannot find module './file.d.cts' or its corresponding type declarations.
+tests/cases/conformance/nonjsExtensions/main.ts(11,19): error TS2307: Cannot find module './file.d.mts' or its corresponding type declarations.
+tests/cases/conformance/nonjsExtensions/main.ts(12,19): error TS2307: Cannot find module './file.d.json.ts' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/nonjsExtensions/package.json (0 errors) ====
@@ -23,10 +23,10 @@ tests/cases/conformance/nonjsExtensions/main.ts(12,19): error TS2691: An import
 !!! error TS2307: Cannot find module './file.jsx' or its corresponding type declarations.
     import def3 from "./file.ts";
                      ~~~~~~~~~~~
-!!! error TS2691: An import path cannot end with a '.ts' extension. Consider importing './file.js' instead.
+!!! error TS2307: Cannot find module './file.ts' or its corresponding type declarations.
     import def4 from "./file.tsx";
                      ~~~~~~~~~~~~
-!!! error TS2691: An import path cannot end with a '.tsx' extension. Consider importing './file.js' instead.
+!!! error TS2307: Cannot find module './file.tsx' or its corresponding type declarations.
     import def5 from "./file.mjs";
                      ~~~~~~~~~~~~
 !!! error TS2307: Cannot find module './file.mjs' or its corresponding type declarations.
@@ -35,22 +35,22 @@ tests/cases/conformance/nonjsExtensions/main.ts(12,19): error TS2691: An import
 !!! error TS2307: Cannot find module './file.cjs' or its corresponding type declarations.
     import def7 from "./file.mts";
                      ~~~~~~~~~~~~
-!!! error TS2691: An import path cannot end with a '.mts' extension. Consider importing './file.mjs' instead.
+!!! error TS2307: Cannot find module './file.mts' or its corresponding type declarations.
     import def8 from "./file.cts";
                      ~~~~~~~~~~~~
-!!! error TS2691: An import path cannot end with a '.cts' extension. Consider importing './file.cjs' instead.
+!!! error TS2307: Cannot find module './file.cts' or its corresponding type declarations.
     import def9 from "./file.d.ts";
                      ~~~~~~~~~~~~~
-!!! error TS2691: An import path cannot end with a '.d.ts' extension. Consider importing './file.js' instead.
+!!! error TS2307: Cannot find module './file.d.ts' or its corresponding type declarations.
     import def10 from "./file.d.cts";
                       ~~~~~~~~~~~~~~
-!!! error TS2691: An import path cannot end with a '.d.cts' extension. Consider importing './file.js' instead.
+!!! error TS2307: Cannot find module './file.d.cts' or its corresponding type declarations.
     import def11 from "./file.d.mts";
                       ~~~~~~~~~~~~~~
-!!! error TS2691: An import path cannot end with a '.d.mts' extension. Consider importing './file.js' instead.
+!!! error TS2307: Cannot find module './file.d.mts' or its corresponding type declarations.
     import def12 from "./file.d.json.ts";
                       ~~~~~~~~~~~~~~~~~~
-!!! error TS2691: An import path cannot end with a '.ts' extension. Consider importing './file.d.json.js' instead.
+!!! error TS2307: Cannot find module './file.d.json.ts' or its corresponding type declarations.
 ==== tests/cases/conformance/nonjsExtensions/file.d.js.ts (0 errors) ====
     declare var bad: "bad1";
     export default bad;

tests/baselines/reference/tsserver/plugins/getSupportedCodeFixes-can-be-proxied.js

@@ -1029,7 +1029,6 @@ Info 32   [00:01:13.000] response:
         "2685",
         "2687",
         "2688",
-        "2691",
         "2692",
         "2694",
         "2695",

tests/cases/conformance/moduleResolution/allowImportingTsExtensions.ts

@@ -27,3 +27,6 @@ import type {} from "./tsx.d.ts";
 import {} from "./dts.js";
 import {} from "./dts.ts";
 import type {} from "./dts.d.ts";
+
+// @Filename: /c.ts
+import {} from "./thisfiledoesnotexist.ts";