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

[alan-agius4]

TypeScript Version: 2.7.0-dev.20171221

Code

// foo.ts
import { WatchOptions } from "cpx";
export let x: WatchOptions;

// bar.ts
import { x } from "./foo";
export const x2 = x;

Just for the sake of the above you can install only @types/cpx

Expected behavior:
No error and the external module interface is named.

Actual behavior:

Exported variable 'x2' has or is using name 'WatchOptions' from external module "C:/git/xxxx/node_modules/@types/cpx/index" but cannot be named.

Related to #20657 but it seems this only solved local non node_modules imports

[ajafff]

Duplicate of #9944