In new Promise, default T to void

[ghost]

Currently the following is a compile error:

new Promise(resolve => { resolve()) };

Because the constructor provides:

resolve: [T] extends [void] ? (value?: T | PromiseLike<T>) => void : (value: T | PromiseLike<T>) => void

Since there's no way to infer T, it is {} by default.
Before #22772, value was always optional and there was no problem. But now many DefinitelyTyped tests are failing because they rely on being able to call resolve() without providing an explicit type argument.
I think void makes a more sensible default than {}, which would fix the issue, but would technically be a breaking change because new Promise(resolve => { resolve({}); }) will now be broken.
(CC @falsandtru)

[falsandtru]

LGTM

[falsandtru]

I found another problem. If Promise has an uninstantiated type parameter, we can't call resolve. So #22772 should be reverted.

<T>(a: T) => new Promise<T>(resolve => resolve(a)); // error

[ghost]

Looks like that's due to #7294 -- but if we're not fixing that soon we should probably revert #22772.

[falsandtru]

Now working on #23545.