`Assoc: Trait` constraints with projection types in generics fail to type-check

I tried this code:

pub trait TriviallyProject {
    type Out;
}

impl TriviallyProject for () {
    type Out = ();
}

pub trait MyTrait<T> {
    type Assoc;
}

fn meow<T: MyTrait<(), Assoc: Default>>() {}

fn mewo<T: MyTrait<<() as TriviallyProject>::Out, Assoc: Default>>() {}

I expected to see this happen: both meow and mewo should compile since () and <() as TriviallyProject>::Out should normalize to the same type

Instead, this happened:

error[E0277]: the trait bound `T: MyTrait<()>` is not satisfied
  --> src/lib.rs:15:1
   |
15 | fn mewo<T: MyTrait<<() as TriviallyProject>::Out, Assoc: Default>>() {}
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `MyTrait<()>` is not implemented for `T`

error[E0277]: the trait bound `T: MyTrait<()>` is not satisfied
  --> src/lib.rs:15:12
   |
15 | fn mewo<T: MyTrait<<() as TriviallyProject>::Out, Assoc: Default>>() {}
   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `MyTrait<()>` is not implemented for `T`

Here's a playground link.

Meta

rustc --version --verbose:

% rustc +nightly --version --verbose
rustc 1.95.0-nightly (1ed488274 2026-02-25)
binary: rustc
commit-hash: 1ed488274bec5bf5cfe6bf7a1cc089abcc4ebd68
commit-date: 2026-02-25
host: aarch64-apple-darwin
release: 1.95.0-nightly
LLVM version: 22.1.0

Start by reproducing the generic example from the issue with the linked Rust Playground and the reported nightly compiler version. Trace how rustc handles the MyTrait<<() as TriviallyProject>::Out> bound, then add a regression test showing that the projection-normalized form type-checks like MyTrait<()>.