symbolToName does handle exports of namespaces

TypeScript Version: 3.2.2

Search Terms: symbolToName, exports, declaration, .d.ts

TypeScript cannot emit the name for a symbol that's declared in an inner namespace but re-exported in the outer namespace. That is, emitting the type name of a symbol does not take an alias created by an export {x as y} statement into account.

This comes up when trying to use the chrome.debugger declaration file. Because debugger is a reserved keyword, the .d.ts is defined using a fake, unexported inner namespace called _debugger, and re-exports it using export {_debugger as debugger};. TypeScript then cannot produce .d.ts files when trying to generate the name for a symbol.

Code

// decl.d.ts
declare module chrome {
  namespace _debugger {
    export class Foo {}
  }
  export function getFoo(): debugger.Foo;
  export {_debugger as debugger};
}

// user.ts
export const x = chrome.getFoo();

Run tsc --declaration.

Expected behavior:

// user.d.ts
export declare const x: chrome.debugger.Foo;

Actual behavior:

test.ts:1:14 - error TS4025: Exported variable 'x' has or is using private name '_debugger.Foo'.

1 export const x = chrome.getFoo();
               ~

Playground Link: n/a

Related Issues:

Reproduce the issue with decl.d.ts and user.ts by running tsc --declaration, then trace the compiler's symbolToName handling for the re-exported _debugger namespace. Compare the generated declaration with the expected chrome.debugger.Foo name and use the existing compiler tests around declaration emit if available to verify the fix.