[nll] unresolved inference variable in outlives: _#3t #53568
Description
The latest crater run reported some ICE errors that look very similar to #52057 (but are potentially different). This crate is small but pretty involved with its wrappers over hyper, tokio, and futures, resulting in a lot of associated types and bounds, and some of those 'static bounds might have a weird interaction with the NLL typeck, impl Trait, and maybe delay_span_bug.
@lqd minimized it to only one such error, but note that the real code has 5 or 6 of them, so it would be good to verify any potential fix on the hyper-stub crate itself rather than just this minimized repro. Playground.