Stabilize `async fn` and return-position `impl Trait` in trait by compiler-errors · Pull Request #115822 · rust-lang/rust
github.com
Stabilization report This report proposes the stabilization of #![feature(return_position_impl_trait_in_trait)] (RPITIT) and #![feature(async_fn_in_trait)] (AFIT). These are both long awaited featu...

Post stolen from Reddit. According to a Reddit comment, this doesn’t solve expressing Send/Sync requirements yet.