Exported variable 'X' has or is using name 'Y' from external module "Z" but cannot be named.

[robyoder]

TypeScript Version: 2.7.0-dev.20171212

Code

// thingA.ts
export interface ThingA { }

// thingB.ts
export interface ThingB { }

// things.ts
export { ThingA } from "./thingA";
export * from "./thingB";

// index.ts
import * as things from "./things";
export const thing1 = (param: things.ThingA) => null;
export const thing2 = (param: things.ThingB) => null;

// tsconfig.json
{
  "compilerOptions": {
    "declaration": true
  }
}

Expected behavior:

Project compiles without errors.

Actual behavior:

index.ts(3,14): error TS4023: Exported variable 'thing2' has or is using name 'ThingB' from external module "/Users/rob/Projects/tsctest/thingB" but cannot be named.

Additional information:

@weswigham fixed the following very similar issues in #19852:

• Object detection for "Exported variable has or is using name from external module" #5938
• “cannot be named” when generating declarations for re-exported classes #8612
• Declaration emit for aliased exports used in export assignments is broken #19825

In fact, before his fix, line 2 of index.ts would also fail.

I've pushed this repro as a project here: https://github.com/robyoder/tsctest

[johnpapa]

@mhegazy thanks for fixing this .. can you clarify what we need t do to get this fix?

[mhegazy]

typescript@rc or typescript@next should have the fix. the fix should also be included in typescript@2.7.1 coming out before the end of the month.

[robyoder]

Super weird: This issue is not fixed when using a type named Account, but it's fixed for everything else. Opened #21313.