Do not do this in JS files, rationale in comment

Author: jakebailey

src/compiler/checker.ts

@@ -5836,9 +5836,11 @@ namespace ts {
                 //
                 // We check that this signature's declaration is within the existing enclosing declaration so we don't pull
                 // in types from other files; if it is outside of the enclosing declaration, then we shouldn't be able to
-                // access those parameter types via typeof anyway.
+                // access those parameter types via typeof anyway. The declaration should also not be in a JS file; those can
+                // only be typed via JSDoc, but JSDoc annotations appear outside of the function and therefore are not in
+                // the function's scope, unlike true type annotations.
                 const saveEnclosingDeclaration = context.enclosingDeclaration;
-                if (signature.declaration && saveEnclosingDeclaration && findAncestor(signature.declaration, (n) => n === saveEnclosingDeclaration)) {
+                if (signature.declaration && !isInJSFile(signature.declaration) && saveEnclosingDeclaration && findAncestor(signature.declaration, (n) => n === saveEnclosingDeclaration)) {
                     context.enclosingDeclaration = signature.declaration;
                 }
 

tests/baselines/reference/jsDeclarationsFunctions.js

@@ -164,7 +164,7 @@ declare class Cls {
 export function g(a: {
     x: string;
 }, b: {
-    y: typeof import(".").b;
+    y: typeof b;
 }): void;
 /**
  * @param {{x: string}} a
@@ -173,6 +173,6 @@ export function g(a: {
 declare function hh(a: {
     x: string;
 }, b: {
-    y: typeof import(".").b;
+    y: typeof b;
 }): void;
 export { hh as h, i as ii, j as jj };

tests/baselines/reference/jsDeclarationsImportAliasExposedWithinNamespace.js

@@ -92,6 +92,3 @@ import { myTypes } from "./file.js";
 export const testFnTypes: {
     [x: string]: any;
 };
-export namespace testFnTypes {
-    type input = boolean | myTypes.typeC;
-}

tests/baselines/reference/jsDeclarationsImportAliasExposedWithinNamespaceCjs.js

@@ -96,69 +96,4 @@ export const testFnTypes: {
 export namespace testFnTypes {
     type input = boolean | myTypes.typeC;
 }
-export namespace testFnTypes {
-    type input = boolean | myTypes.typeC;
-}
 import { myTypes } from "./file.js";
-
-
-//// [DtsFileErrors]
-
-
-tests/cases/conformance/jsdoc/declarations/file2.d.ts(18,10): error TS2300: Duplicate identifier 'input'.
-tests/cases/conformance/jsdoc/declarations/file2.d.ts(21,10): error TS2300: Duplicate identifier 'input'.
-
-
-==== tests/cases/conformance/jsdoc/declarations/file2.d.ts (2 errors) ====
-    /** @typedef {boolean|myTypes.typeC} testFnTypes.input */
-    /**
-     * @function testFn
-     * @description A test function.
-     * @param {testFnTypes.input} input - Input.
-     * @returns {number|null} Result.
-     */
-    export function testFn(input: testFnTypes.input): number | null;
-    /**
-     * @namespace testFnTypes
-     * @global
-     * @type {Object<string,*>}
-     */
-    export const testFnTypes: {
-        [x: string]: any;
-    };
-    export namespace testFnTypes {
-        type input = boolean | myTypes.typeC;
-             ~~~~~
-!!! error TS2300: Duplicate identifier 'input'.
-    }
-    export namespace testFnTypes {
-        type input = boolean | myTypes.typeC;
-             ~~~~~
-!!! error TS2300: Duplicate identifier 'input'.
-    }
-    import { myTypes } from "./file.js";
-    
-==== /.src/tests/cases/conformance/jsdoc/declarations/file.d.ts (0 errors) ====
-    /**
-     * @namespace myTypes
-     * @global
-     * @type {Object<string,*>}
-     */
-    export const myTypes: {
-        [x: string]: any;
-    };
-    export namespace myTypes {
-        type typeA = string | RegExp | Array<string | RegExp>;
-        type typeB = {
-            /**
-             * - Prop 1.
-             */
-            prop1: myTypes.typeA;
-            /**
-             * - Prop 2.
-             */
-            prop2: string;
-        };
-        type typeC = myTypes.typeB | Function;
-    }
-    

tests/baselines/reference/jsDeclarationsParameterTagReusesInputNodeInEmit1.js

@@ -86,7 +86,7 @@ declare const couldntThinkOfAny: {};
  * @param {InstanceType<BaseFactory["Base"]>} base
  * @returns {InstanceType<BaseFactory["Base"]>}
  */
-declare function test(base: InstanceType<BaseFactory["Base"]>): {};
+declare function test(base: InstanceType<BaseFactory["Base"]>): InstanceType<BaseFactory["Base"]>;
 type BaseFactory = {
     (): {};
     Base: {

tests/baselines/reference/jsDeclarationsParameterTagReusesInputNodeInEmit2.js

@@ -62,5 +62,5 @@ declare class Base {
  * @param {InstanceType<BaseFactory["Base"]>} base
  * @returns {InstanceType<BaseFactory["Base"]>}
  */
-declare function test(base: InstanceType<BaseFactory["Base"]>): {};
+declare function test(base: InstanceType<BaseFactory["Base"]>): InstanceType<BaseFactory["Base"]>;
 type BaseFactory = typeof import('./base');

tests/baselines/reference/typeTagOnPropertyAssignment.types

@@ -13,7 +13,7 @@ const o = {
     /** @type {() => 'b'} */
     n: () => 'b'
 >n : () => 'b'
->() => 'b' : () => "b"
+>() => 'b' : () => 'b'
 >'b' : "b"
 
 };