Recent rust nigthly version can't compile previously working code, duo to compiler not being able to find associated type inside a "async fn in trait" definition.

Code

Compiling this code:

#![allow(async_fn_in_trait)] pub trait foo {} pub trait bar { type foo: foo; } pub trait baz { async fn boom<X: bar>() -> Result<(), X::foo>; }

I expected to see this happen: In previous version up to nightly-2024-10-28 this code compiled

Instead, this happened: It stoped compiling with the error

error[E0220]: associated type `foo` not found for `X` 8 | async fn boom<X: bar>() -> Result<(), X::foo>; | ^^^ there is an associated type `foo` in the trait `bar` 

Version it worked on

nightly-2024-10-28

Version with regression

nightly-2024-10-29

rustc --version --verbose:

rustc 1.84.0-nightly (1e4f10ba6 2024-10-29) binary: rustc commit-hash: 1e4f10ba6476e48a42a79b9f846a2d9366525b9e commit-date: 2024-10-29 host: x86_64-unknown-linux-gnu release: 1.84.0-nightly LLVM version: 19.1.1 

No, code just stops compiling.