Awaiting a non-promise doesn't error

[tinganho]

I'm kind of expecting this to throw an error:

async function test() {
    await []; // no error
}

I did a mistake of not using Promise.all():

async function test() {
    let promises: Promise<any>[] = [];
    // ...
    await Promise.all(promises); // no error
}

And it would be helpful if TS could help me catch those mistakes.

[yortus]

I agree this is annoying as I've also occasionally put the wrong thing after await and didn't get any compiler errors.

Having said that, awaiting a non-promise is valid under the spec (although it comes under the heading 'debatable syntax'), and it has well-defined semantics. It is actually convenient in some cases (eg awaiting a value of type T|Promise<T>).

I agree it's annoying but I would not wish something that's currently valid in the ECMA proposal, and that is useful at times, to become an error in TypeScript.

If someone could think up a 'best of both worlds' approach, I'd be all for that.

[yortus]

Also, this is a duplicate of #8310, and there's a lot more discussion there.

[tinganho]

Yes duplicate of #8310.