//@ known-bug: rust-lang/rust#126725 trait Foo { fn foo<'a>(&'a self) -> <&'a impl Sized as Bar>::Output; } trait Bar { type Output; } struct X(i32); impl<'a> Bar for &'a X { type Output = &'a i32; } impl Foo for X { fn foo<'a>(&'a self) -> <&'a Self as Bar>::Output { &self.0 } }