TAIT still captures lifetime generics implicitely

[aliemjay]

This code should pass but it doesn't:

#![feature(type_alias_impl_trait)]

trait Callable {
    type Output;
    fn call() -> Self::Output;
}

impl<'a> Callable for &'a () {
    type Output = impl Sized;
    fn call() -> Self::Output {}
}

fn test<'a>() -> impl Sized {
    <&'a () as Callable>::call()
    //~^ ERROR hidden type captures lifetime that does not appear in bounds
}

This is #96996 resurrected. Cc @oli-obk.

@rustbot label F-type_alias_impl_trait C-bug T-compiler T-types

[oli-obk]

Oh heh, I fixed the situation for registering the hidden type but didn't allow implying anything from that.