tests/ui/impl-trait/issue-99642.rs - toolchain/rustc - Git at Google

 //@ check-pass

 fn test() -> impl Iterator<Item = impl Sized> {
     Box::new(0..) as Box<dyn Iterator<Item = _>>
 }

 fn main() {}
	//@ check-pass

	fn test() -> impl Iterator<Item = impl Sized> {
	Box::new(0..) as Box<dyn Iterator<Item = _>>
	}

	fn main() {}