Change `impl Future for Either` to `Output = Either` about either

[thomaseizinger]

FWIW, a not unified output would have been more powerful because you can always call into_inner if they end up being the same type.

Not sure if you ever plan on doing 2.0 but that could be a consideration :)

[cuviper]

Is there a reason you're not using futures::future::Either for that?

[thomaseizinger]

Is there a reason you're not using futures::future::Either for that?

I guess we could yeah! I'll try and report back.

[thomaseizinger]

It doesn't work at the moment because project is not exposed publicly. However, I think from the previous responses, people are okay with adding it so I'll submit a PR now.

Edit: PR submitted here: rust-lang/futures-rs#2691

[thomaseizinger]

Another thing I just discovered is that futures::Either has a - IMO - very weird implementation of Future:

impl<A, B> Future for Either<A, B>
where
    A: Future,
    B: Future<Output = A::Output>,
{
    type Output = A::Output;

    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        match self.project() {
            Either::Left(x) => x.poll(cx),
            Either::Right(x) => x.poll(cx),
        }
    }
}

I would have expected that a Either<F1, F2> yields me another Either type but the implementation in futures forces both futures to resolve to the same type.

[thomaseizinger]

Would you be up for merging an implementation of the futures traits that doesn't try to be clever and simply sets all associated types to Either, i.e. Future::Output, Stream::Item, etc

[cuviper]

Ah, note that Future is a re-export from core, and #77 already implemented that with a unified Output. I'm not sure why I did that -- probably just because that's how we treat Iterator too.

[thomaseizinger]

Ah, note that Future is a re-export from core, and #77 already implemented that with a unified Output. I'm not sure why I did that -- probably just because that's how we treat Iterator too.

Dang so that would be a breaking change :(

I guess I'll have to stick with my custom Either type then.