Default `this` value for static promise functions

[a.d.bergi at web.de]

Hi,
I've just got bitten by

    return getError().then(Promise.reject);

where `reject` threw an error that its `this` value was not a Promise constructor.

Would it help to make the `C` constructor (in Promise.resolve, Promise.reject, Promise.all, Promise.race algorithms) default to `Promise` when no `this` value is supplied (throw only if it's there, but not an object and constructor function)?
Or is this considered to be too error-prone with Promise subclassing, where `.then(MyCustomPromise.reject)` would not work as expected (fail silently)?

regards,
 Bergi