Hey @Esteban Küber -- we never got a chance to dig more into your thoughts re:
async fn diagnostics. I thought it was a good idea in general though to try and focus our immediate efforts on "polish", in the form of diagnostics and other small fixes. Not sure if you had a more concrete list of scenarios that you were concerned about? I forget what you said.
I have this pr that brings a semblance of parity between e0308 and e0277 errors for the same mistake https://github.com/rust-lang/rust/pull/63870
But the way we make new obligations with spans pointing at the fn call instead of the arg that failed to meet the obligation doesn't allow me to give a suggestion and is a long standing issue that causes confusion in a regular basis
That being said i would like to see people that are using async often to file tickets about errors that are not at parity
The improvements for async will be improvements for assoc types and for imp trait errors, so I can look at the backlog for those
Another thing that might pop up https://github.com/rust-lang/rust/issues/63167#issuecomment-524728779