os-rust/tests/ui/issues/issue-33461.rs

// run-pass
#![allow(unused_variables)]
use std::marker::PhantomData;

struct TheType<T> {
    t: PhantomData<T>
}

pub trait TheTrait {
    type TheAssociatedType;
}

impl TheTrait for () {
    type TheAssociatedType = ();
}

pub trait Shape<P: TheTrait> {
    fn doit(&self) {
    }
}

impl<P: TheTrait> Shape<P> for TheType<P::TheAssociatedType> {
}

fn main() {
    let ball = TheType { t: PhantomData };
    let handle: &dyn Shape<()> = &ball;
}