feat: emitExtension can not be .d.ts now

Author: Jack-Works

src/compiler/checker.ts

@@ -2721,8 +2721,8 @@ namespace ts {
                     const tsExtension = tryExtractTSExtension(moduleReference);
                     if (tsExtension) {
                         // Support import .ts and .tsx file for environment like deno
-                        if (fileExtensionIs(moduleReference, Extension.Dts)) {
-                            const diag = Diagnostics.An_import_path_cannot_end_with_a_0_extension_Consider_importing_1_instead;
+                        if (!compilerOptions.emitExtension || fileExtensionIs(moduleReference, Extension.Dts)) {
+                            const diag = Diagnostics.An_import_path_cannot_end_with_a_0_extension_Consider_importing_1_instead_If_the_extension_is_expected_please_set_emitExtension_in_the_compilerConfig;
                             error(errorNode, diag, tsExtension, removeExtension(moduleReference, tsExtension));
                         }
                     }

src/compiler/diagnosticMessages.json

@@ -1059,7 +1059,6 @@
         "category": "Error",
         "code": 1360
     },
-
     "The types of '{0}' are incompatible between these types.": {
         "category": "Error",
         "code": 2200
@@ -1088,7 +1087,6 @@
         "code": 2205,
         "elidedInCompatabilityPyramid": true
     },
-
     "Duplicate identifier '{0}'.": {
         "category": "Error",
         "code": 2300
@@ -2269,7 +2267,6 @@
         "category": "Error",
         "code": 2614
     },
-
     "Cannot augment module '{0}' with value exports because it resolves to a non-module entity.": {
         "category": "Error",
         "code": 2649
@@ -2426,7 +2423,7 @@
         "category": "Error",
         "code": 2689
     },
-    "An import path cannot end with a '{0}' extension. Consider importing '{1}' instead.": {
+    "An import path cannot end with a '{0}' extension. Consider importing '{1}' instead. If the extension is expected, please set 'emitExtension' in the compilerConfig.": {
         "category": "Error",
         "code": 2691
     },
@@ -2791,7 +2788,6 @@
         "category": "Error",
         "code": 2781
     },
-
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
         "code": 4000
@@ -3156,7 +3152,6 @@
         "category": "Error",
         "code": 4110
     },
-
     "The current host does not support the '{0}' option.": {
         "category": "Error",
         "code": 5001
@@ -4197,7 +4192,6 @@
         "category": "Message",
         "code": 6302
     },
-
     "Composite projects may not disable declaration emit.": {
         "category": "Error",
         "code": 6304
@@ -4358,7 +4352,6 @@
         "category": "Message",
         "code": 6383
     },
-
     "The expected type comes from property '{0}' which is declared here on type '{1}'": {
         "category": "Message",
         "code": 6500
@@ -4383,15 +4376,18 @@
         "category": "Message",
         "code": 6505
     },
-    "Emit extension must start with '.', but here has '{0}', try to replace it with '.{0}'.": {
+    "emitExtension must start with '.', but here has '{0}', try to replace it with '.{0}'.": {
         "category": "Error",
         "code": 6506
     },
     "emitExtension can only be \".jsx\" when JSX is set to \"preserve\"": {
         "category": "Error",
         "code": 6507
     },
-
+    "emitExtension can not be \".d.ts\"": {
+        "category": "Error",
+        "code": 6508
+    },
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005
@@ -4586,7 +4582,6 @@
         "category": "Error",
         "code": 7055
     },
-
     "You cannot rename this element.": {
         "category": "Error",
         "code": 8000
@@ -4819,7 +4814,6 @@
         "category": "Error",
         "code": 18003
     },
-
     "File is a CommonJS module; it may be converted to an ES6 module.": {
         "category": "Suggestion",
         "code": 80001
@@ -4852,7 +4846,6 @@
         "category": "Suggestion",
         "code": 80008
     },
-
     "Add missing 'super()' call": {
         "category": "Message",
         "code": 90001
@@ -5353,7 +5346,6 @@
         "category": "Message",
         "code": 95095
     },
-
     "No value exists in scope for the shorthand property '{0}'. Either declare one or provide an initializer.": {
         "category": "Error",
         "code": 18004

src/compiler/program.ts

@@ -3162,12 +3162,16 @@ namespace ts {
                 });
             }
 
-            if (options.emitExtension && !startsWith(options.emitExtension, ".")) {
-                createOptionValueDiagnostic("emitExtension", Diagnostics.Emit_extension_must_start_with_but_here_has_0_try_to_replace_it_with_0, options.emitExtension);
-            }
-
-            if (options.emitExtension && options.emitExtension !== ".jsx" && options.jsx === JsxEmit.Preserve) {
-                createOptionValueDiagnostic("emitExtension", Diagnostics.emitExtension_can_only_be_jsx_when_JSX_is_set_to_preserve, options.emitExtension);
+            if (options.emitExtension) {
+                if (!startsWith(options.emitExtension, ".")) {
+                    createOptionValueDiagnostic("emitExtension", Diagnostics.emitExtension_must_start_with_but_here_has_0_try_to_replace_it_with_0, options.emitExtension);
+                }
+                if (options.emitExtension !== Extension.Jsx && options.jsx === JsxEmit.Preserve) {
+                    createOptionValueDiagnostic("emitExtension", Diagnostics.emitExtension_can_only_be_jsx_when_JSX_is_set_to_preserve, options.emitExtension);
+                }
+                if (options.emitExtension === Extension.Dts) {
+                    createOptionValueDiagnostic("emitExtension", Diagnostics.emitExtension_can_not_be_d_ts, options.emitExtension);
+                }
             }
 
             // Verify that all the emit files are unique and don't overwrite input files

tests/baselines/reference/emitExtensionDTS.errors.txt

@@ -0,0 +1,11 @@
+tests/cases/compiler/emitExtensionDTS.ts(2,20): error TS2691: An import path cannot end with a '.d.ts' extension. Consider importing './file' instead. If the extension is expected, please set 'emitExtension' in the compilerConfig.
+
+
+==== tests/cases/compiler/emitExtensionDTS.ts (1 errors) ====
+    // @Filename 1.ts
+    import * as t from './file.d.ts'
+                       ~~~~~~~~~~~~~
+!!! error TS2691: An import path cannot end with a '.d.ts' extension. Consider importing './file' instead. If the extension is expected, please set 'emitExtension' in the compilerConfig.
+    console.log(t)
+    
+    

tests/baselines/reference/emitExtensionDTS.js

@@ -0,0 +1,13 @@
+//// [emitExtensionDTS.ts]
+// @Filename 1.ts
+import * as t from './file.d.ts'
+console.log(t)
+
+
+
+//// [emitExtensionDTS.mjs]
+"use strict";
+exports.__esModule = true;
+// @Filename 1.ts
+var t = require("./file.d.ts");
+console.log(t);

tests/baselines/reference/emitExtensionDTS.symbols

@@ -0,0 +1,12 @@
+=== tests/cases/compiler/emitExtensionDTS.ts ===
+// @Filename 1.ts
+import * as t from './file.d.ts'
+>t : Symbol(t, Decl(emitExtensionDTS.ts, 1, 6))
+
+console.log(t)
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>t : Symbol(t, Decl(emitExtensionDTS.ts, 1, 6))
+
+

tests/baselines/reference/emitExtensionDTS.types

@@ -0,0 +1,13 @@
+=== tests/cases/compiler/emitExtensionDTS.ts ===
+// @Filename 1.ts
+import * as t from './file.d.ts'
+>t : any
+
+console.log(t)
+>console.log(t) : void
+>console.log : (message?: any, ...optionalParams: any[]) => void
+>console : Console
+>log : (message?: any, ...optionalParams: any[]) => void
+>t : any
+
+

tests/baselines/reference/emitExtensionInvalidValue.errors.txt

@@ -1,7 +1,7 @@
-error TS6506: Emit extension must start with '.', but here has 'ts', try to replace it with '.ts'.
+error TS6506: emitExtension must start with '.', but here has 'ts', try to replace it with '.ts'.
 
 
-!!! error TS6506: Emit extension must start with '.', but here has 'ts', try to replace it with '.ts'.
+!!! error TS6506: emitExtension must start with '.', but here has 'ts', try to replace it with '.ts'.
 ==== tests/cases/compiler/0.ts (0 errors) ====
     export default 1
 

tests/baselines/reference/moduleResolutionNoTs.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/user.ts(1,15): error TS2691: An import path cannot end with a '.d.ts' extension. Consider importing './z' instead.
+tests/cases/compiler/user.ts(1,15): error TS2691: An import path cannot end with a '.d.ts' extension. Consider importing './z' instead. If the extension is expected, please set 'emitExtension' in the compilerConfig.
 
 
 ==== tests/cases/compiler/z.d.ts (0 errors) ====
@@ -8,7 +8,7 @@ tests/cases/compiler/user.ts(1,15): error TS2691: An import path cannot end with
 ==== tests/cases/compiler/user.ts (1 errors) ====
     import z from "./z.d.ts";
                   ~~~~~~~~~~
-!!! error TS2691: An import path cannot end with a '.d.ts' extension. Consider importing './z' instead.
+!!! error TS2691: An import path cannot end with a '.d.ts' extension. Consider importing './z' instead. If the extension is expected, please set 'emitExtension' in the compilerConfig.
 
     // Making sure the suggested fixes are valid:
     import z2 from "./z";

tests/cases/compiler/emitExtensionDTS.ts

@@ -0,0 +1,6 @@
+// @emitExtension: .mjs
+
+// @Filename 1.ts
+import * as t from './file.d.ts'
+console.log(t)
+