Reproduction steps

Setup

npm install

Control

First run

node ./node_modules/.bin/tsc -b

Observe that declarations/b.d.ts contains

import { Foo } from "../projA";
export type Bar = {
  [Foo.A]: 1;
  [Foo.B]: 2;
};

Test

Now run

node ./transpile.mjs tsconfig.json declarations

Observe that declarations/b.d.ts contains

export type Bar = {};