False-positive type-mismatch error with generic future

[aidanalphafund]

Description

It seems rust analyzer can't resolve the output type of a future if that output is generic on another future's output type, leading to erroneous type-mismatch errors.

I initially ran into this using try_for_each_concurrent on a stream, but managed to narrow the problem to a much simpler reproduction.

Reproduction (playground)

use std::future::Future;

async fn reproduction() -> usize {
    MyFut(async { 3 }).await
}

struct MyFut<Fut>(Fut);

impl<Fut: Future> Future for MyFut<Fut> {
    type Output = Fut::Output;

    fn poll(
        self: std::pin::Pin<&mut Self>,
        cx: &mut std::task::Context<'_>,
    ) -> std::task::Poll<Self::Output> {
        todo!()
    }
}

rust-analyzer version: f94fa62 2022-05-30 stable
rustc version: rustc 1.61.0 (fe5b13d68 2022-05-18)