fix(39373): add diagnostic message about using a private name for class declarations without name (#39567)

src/compiler/diagnosticMessages.json

@@ -3057,6 +3057,10 @@
         "category": "Error",
         "code": 4020
     },
+    "'extends' clause of exported class has or is using private name '{0}'.": {
+        "category": "Error",
+        "code": 4021
+    },
     "'extends' clause of exported interface '{0}' has or is using private name '{1}'.": {
         "category": "Error",
         "code": 4022

src/compiler/transformers/declarations/diagnostics.ts

@@ -447,11 +447,12 @@ namespace ts {
         function getHeritageClauseVisibilityError(): SymbolAccessibilityDiagnostic {
             let diagnosticMessage: DiagnosticMessage;
             // Heritage clause is written by user so it can always be named
-            if (node.parent.parent.kind === SyntaxKind.ClassDeclaration) {
+            if (isClassDeclaration(node.parent.parent)) {
                 // Class or Interface implemented/extended is inaccessible
                 diagnosticMessage = isHeritageClause(node.parent) && node.parent.token === SyntaxKind.ImplementsKeyword ?
                     Diagnostics.Implements_clause_of_exported_class_0_has_or_is_using_private_name_1 :
-                    Diagnostics.extends_clause_of_exported_class_0_has_or_is_using_private_name_1;
+                        node.parent.parent.name ? Diagnostics.extends_clause_of_exported_class_0_has_or_is_using_private_name_1 :
+                            Diagnostics.extends_clause_of_exported_class_has_or_is_using_private_name_0;
             }
             else {
                 // interface is inaccessible

tests/baselines/reference/declarationEmitExpressionInExtends6.errors.txt

@@ -0,0 +1,15 @@
+/b.ts(2,30): error TS4021: 'extends' clause of exported class has or is using private name 'Foo'.
+
+
+==== /b.ts (1 errors) ====
+    const { Foo } = require("./a");
+    export default class extends Foo {}
+                                 ~~~
+!!! error TS4021: 'extends' clause of exported class has or is using private name 'Foo'.
+    
+==== /node_modules/@types/node/index.d.ts (0 errors) ====
+    declare const require: any;
+    
+==== /a.ts (0 errors) ====
+    export class Foo {}
+    

tests/baselines/reference/declarationEmitExpressionInExtends6.js

@@ -0,0 +1,38 @@
+//// [tests/cases/compiler/declarationEmitExpressionInExtends6.ts] ////
+
+//// [index.d.ts]
+declare const require: any;
+
+//// [a.ts]
+export class Foo {}
+
+//// [b.ts]
+const { Foo } = require("./a");
+export default class extends Foo {}
+
+
+//// [b.js]
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = function (d, b) {
+        extendStatics = Object.setPrototypeOf ||
+            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+            function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
+        return extendStatics(d, b);
+    };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+exports.__esModule = true;
+var Foo = require("./a").Foo;
+var default_1 = /** @class */ (function (_super) {
+    __extends(default_1, _super);
+    function default_1() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    return default_1;
+}(Foo));
+exports["default"] = default_1;

tests/baselines/reference/declarationEmitExpressionInExtends6.symbols

@@ -0,0 +1,12 @@
+=== /b.ts ===
+const { Foo } = require("./a");
+>Foo : Symbol(Foo, Decl(b.ts, 0, 7))
+>require : Symbol(require, Decl(index.d.ts, 0, 13))
+
+export default class extends Foo {}
+>Foo : Symbol(Foo, Decl(b.ts, 0, 7))
+
+=== /node_modules/@types/node/index.d.ts ===
+declare const require: any;
+>require : Symbol(require, Decl(index.d.ts, 0, 13))
+

tests/baselines/reference/declarationEmitExpressionInExtends6.types

@@ -0,0 +1,14 @@
+=== /b.ts ===
+const { Foo } = require("./a");
+>Foo : any
+>require("./a") : any
+>require : any
+>"./a" : "./a"
+
+export default class extends Foo {}
+>Foo : any
+
+=== /node_modules/@types/node/index.d.ts ===
+declare const require: any;
+>require : any
+

tests/cases/compiler/declarationEmitExpressionInExtends6.ts

@@ -0,0 +1,14 @@
+// @module: commonjs
+// @declaration: true
+// @types: node
+// @currentDirectory: /
+
+// @Filename: /node_modules/@types/node/index.d.ts
+declare const require: any;
+
+// @Filename: /a.ts
+export class Foo {}
+
+// @Filename: /b.ts
+const { Foo } = require("./a");
+export default class extends Foo {}