2 #![allow(unused_must_use)]
3 fn bug<T>() -> impl Iterator<Item = [(); { |x: u32| { x }; 4 }]> {
7 fn ok<T>() -> Box<dyn Iterator<Item = [(); { |x: u32| { x }; 4 }]>> {
8 Box::new(std::iter::empty())
12 for _item in ok::<u32>() {}
13 for _item in bug::<u32>() {}