// check-pass #![feature(specialization)] #![feature(lint_reasons)] #![allow(incomplete_features)] pub trait Foo { fn bar(&self) -> impl Sized; } impl Foo for U where U: Copy, { #[expect(refining_impl_trait)] fn bar(&self) -> U { *self } } impl Foo for i32 {} fn main() { let _: i32 = 1i32.bar(); }