looking up hidden types in the opaque storage may need to consider duplicate entries

[lcnr]

only necessary after rust-lang/rust#140497 rust-lang/rust#140405

my worry is something like this, even if I can't quite exploit it

trait Trait {
    type Assoc;
}
impl<T> Trait for T {
    type Assoc = String;
}

fn get_assoc<T: Trait>(x: T) -> T::Assoc {
    loop {}
}
fn foo<T: Copy + Default>(x: T) -> impl Trait<Assoc = String> + Default + Copy {
    let mut y = Default::default();
    let mut inf1 = Default::default();
    inf1 = foo(y);
    let inf = Default::default();
    if false {
        return inf;
    }
    y = x;
    get_assoc(inf1).len()
} 

TODO: lcnr explain/figure out