Fix error on interfaces in .js files (#35969)

* Use the correct error message.

* Accepted baselines.

Author: DanielRosenwasser

src/compiler/program.ts

@@ -1837,7 +1837,9 @@ namespace ts {
                             }
                             break;
                         case SyntaxKind.InterfaceDeclaration:
-                            diagnostics.push(createDiagnosticForNode(node, Diagnostics.Interface_declaration_cannot_have_implements_clause));
+                            const interfaceKeyword = tokenToString(SyntaxKind.InterfaceKeyword);
+                            Debug.assertDefined(interfaceKeyword);
+                            diagnostics.push(createDiagnosticForNode(node, Diagnostics._0_declarations_can_only_be_used_in_TypeScript_files, interfaceKeyword));
                             return;
                         case SyntaxKind.ModuleDeclaration:
                             const moduleKeyword = node.flags & NodeFlags.Namespace ? tokenToString(SyntaxKind.NamespaceKeyword) : tokenToString(SyntaxKind.ModuleKeyword);

tests/baselines/reference/getJavaScriptSyntacticDiagnostics6.baseline

@@ -1,8 +1,8 @@
 Syntactic Diagnostics for file '/tests/cases/fourslash/getJavaScriptSyntacticDiagnostics6.ts':
-/tests/cases/fourslash/a.js(1,11): error TS1176: Interface declaration cannot have 'implements' clause.
+/tests/cases/fourslash/a.js(1,11): error TS8006: 'interface' declarations can only be used in TypeScript files.
 
 
 ==== /tests/cases/fourslash/a.js (1 errors) ====
     interface I { }
               ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.

tests/baselines/reference/jsDeclarationsInterfaces.errors.txt

@@ -1,29 +1,29 @@
-tests/cases/conformance/jsdoc/declarations/index.js(4,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(6,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(10,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(31,11): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(35,11): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(39,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(43,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(45,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(49,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(53,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(57,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(61,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(65,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(67,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(71,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(75,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(80,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(84,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(87,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(91,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(95,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(100,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(105,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(107,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(111,18): error TS1176: Interface declaration cannot have 'implements' clause.
-tests/cases/conformance/jsdoc/declarations/index.js(115,18): error TS1176: Interface declaration cannot have 'implements' clause.
+tests/cases/conformance/jsdoc/declarations/index.js(4,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(6,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(10,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(31,11): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(35,11): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(39,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(43,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(45,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(49,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(53,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(57,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(61,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(65,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(67,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(71,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(75,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(80,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(84,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(87,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(91,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(95,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(100,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(105,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(107,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(111,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
+tests/cases/conformance/jsdoc/declarations/index.js(115,18): error TS8006: 'interface' declarations can only be used in TypeScript files.
 
 
 ==== tests/cases/conformance/jsdoc/declarations/index.js (26 errors) ====
@@ -32,17 +32,17 @@ tests/cases/conformance/jsdoc/declarations/index.js(115,18): error TS1176: Inter
 
     export interface A {}
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
 
     export interface B {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         cat: string;
     }
 
     export interface C<T, U> {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         field: T & U;
         optionalField?: T;
         readonly readonlyField: T & U;
@@ -65,135 +65,135 @@ tests/cases/conformance/jsdoc/declarations/index.js(115,18): error TS1176: Inter
 
     interface G {}
               ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
 
     export { G };
 
     interface HH {}
               ~~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
 
     export { HH as H };
 
     export interface I {}
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
     export { I as II };
 
     export { J as JJ };
     export interface J {}
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
 
     export interface K extends I,J {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         x: string;
     }
 
     export interface L extends K {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         y: string;
     }
 
     export interface M<T> {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         field: T;
     }
 
     export interface N<U> extends M<U> {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         other: U;
     }
 
     export interface O {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: string]: string;
     }
 
     export interface P extends O {}
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
 
     export interface Q extends O {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: string]: "ok";
     }
 
     export interface R extends O {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: number]: "ok";
     }
 
     export interface S extends O {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: string]: "ok";
         [idx: number]: never;
     }
 
     export interface T {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: number]: string;
     }
 
     export interface U extends T {}
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
 
 
     export interface V extends T {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: string]: string;
     }
 
     export interface W extends T {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: number]: "ok";
     }
 
     export interface X extends T {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: string]: string;
         [idx: number]: "ok";
     }
 
     export interface Y {
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: string]: {x: number};
         [idx: number]: {x: number, y: number};
     }
 
     export interface Z extends Y {}
                      ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
 
     export interface AA extends Y {
                      ~~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: string]: {x: number, y: number};
     }
 
     export interface BB extends Y {
                      ~~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: number]: {x: 0, y: 0};
     }
 
     export interface CC extends Y {
                      ~~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.
         [idx: string]: {x: number, y: number};
         [idx: number]: {x: 0, y: 0};
     }

tests/baselines/reference/jsFileCompilationInterfaceSyntax.errors.txt

@@ -1,11 +1,11 @@
 error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
-tests/cases/compiler/a.js(1,11): error TS1176: Interface declaration cannot have 'implements' clause.
+tests/cases/compiler/a.js(1,11): error TS8006: 'interface' declarations can only be used in TypeScript files.
 
 
 !!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
 !!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
 ==== tests/cases/compiler/a.js (1 errors) ====
     interface I { }
               ~
-!!! error TS1176: Interface declaration cannot have 'implements' clause.
+!!! error TS8006: 'interface' declarations can only be used in TypeScript files.