Inference hazard due to lazy alias relate: Break it in the old solver?

[compiler-errors]

Lazy alias relate causes us to no longer (incompletely) infer alias args when we don't normalize aliases to infer vars. That causes this code to (rightfully, IMO) fail:

trait Foo {
    type Assoc<'a>;
}

fn foo<'a, T: Foo>(_: <T as Foo>::Assoc<'a>) {}

fn test<'a, T: Foo>() {
    let y: fn(<T as Foo>::Assoc<'a>) = foo;
}

I'd like to prevent this from being more of an issue, but nothing comes to mind for a good scheme to weaken this inference in the old solver. Ideas?

[compiler-errors]

(cannot remember if this is already tracked as an issue lol)

[lcnr]

not sure 😅 doesn't really seem like it... definitely a known issue and I don't see how we can easily change this behavior in the old solver