Fix shaking for functions types with overload signatures (#7036)

Author: kherock

packages/core/integration-tests/test/integration/ts-types/exporting-overload/expected.d.ts

@@ -0,0 +1,5 @@
+import { Named1, Named2 } from "external";
+export function overloaded(arg: string): Named1;
+export function overloaded(arg: number): Named2;
+
+//# sourceMappingURL=types.d.ts.map

packages/core/integration-tests/test/integration/ts-types/exporting-overload/index.ts

@@ -0,0 +1,7 @@
+import {Named1, Named2} from 'external';
+
+export function overloaded(arg: string): Named1;
+export function overloaded(arg: number): Named2;
+export function overloaded(arg: unknown): unknown {
+  return {};
+}

packages/core/integration-tests/test/integration/ts-types/exporting-overload/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "ts-types-exporting-overload",
+  "private": true,
+  "main": "dist/main.js",
+  "types": "dist/types.d.ts",
+  "dependencies": {
+    "external": "*"
+  }
+}

packages/core/integration-tests/test/integration/ts-types/exporting-overload/yarn.lock

@@ -135,6 +135,41 @@ describe('typescript types', function() {
     assert.equal(dist, expected);
   });
 
+  it('should generate ts declarations with export of an overloaded function signature', async function() {
+    let b = await bundle(
+      path.join(__dirname, '/integration/ts-types/exporting-overload/index.ts'),
+    );
+
+    assertBundles(b, [
+      {
+        type: 'js',
+        assets: ['index.ts'],
+      },
+      {
+        type: 'ts',
+        assets: ['index.ts'],
+      },
+    ]);
+
+    let dist = (
+      await outputFS.readFile(
+        path.join(
+          __dirname,
+          '/integration/ts-types/exporting-overload/dist/types.d.ts',
+        ),
+        'utf8',
+      )
+    ).replace(/\r\n/g, '\n');
+    let expected = await inputFS.readFile(
+      path.join(
+        __dirname,
+        '/integration/ts-types/exporting-overload/expected.d.ts',
+      ),
+      'utf8',
+    );
+    assert.equal(dist, expected);
+  });
+
   it('should generate ts declarations with externals', async function() {
     let b = await bundle(
       path.join(__dirname, '/integration/ts-types/externals/index.tsx'),

packages/core/integration-tests/test/ts-types.js

@@ -8,7 +8,7 @@ export type Export =
 export class TSModule {
   imports: Map<string, Import>;
   exports: Array<Export>;
-  bindings: Map<string, any>;
+  bindings: Map<string, Set<any>>;
   names: Map<string, string>;
   used: Set<string>;
 
@@ -37,7 +37,9 @@ export class TSModule {
   }
 
   addLocal(name: string, node: any) {
-    this.bindings.set(name, node);
+    const bindings = this.bindings.get(name) ?? new Set();
+    bindings.add(node);
+    this.bindings.set(name, bindings);
     if (name !== 'default') {
       this.names.set(name, name);
     }

packages/transformers/typescript-types/src/TSModule.js

@@ -64,9 +64,11 @@ export class TSModuleGraph {
       return ts.visitEachChild(node, visit, context);
     };
 
-    let node = module.bindings.get(name);
-    if (node) {
-      ts.visitEachChild(node, visit, context);
+    let bindings = module.bindings.get(name);
+    if (bindings) {
+      for (let node of bindings) {
+        ts.visitEachChild(node, visit, context);
+      }
     }
   }