DefinitelyTyped/types/promise-timeout/promise-timeout-tests.ts

import { timeout, TimeoutError } from "promise-timeout";

function acceptError(e: Error) { }

acceptError(new TimeoutError());

timeout();                       // $ExpectError
timeout(new Promise(() => { })); // $ExpectError

const top = (<T>(x?: T): T => x!)();
type Top = typeof top;
declare function expectPromiseTop(x: Promise<Top>): void;

expectPromiseTop(timeout(new Promise(() => { }), 1000));