// check-pass #[derive(Clone)] struct A<'a, T>(&'a T); impl<'a, T: Copy + 'a> Copy for A<'a, T> {} #[derive(Clone)] struct B<'a, T>(A<'a, T>); // `T: '_` should be implied by `WF(B<'_, T>)`. impl Copy for B<'_, T> {} fn main() {}