1 error: you are implementing `Iterator` on a `Copy` type
2 --> $DIR/copy_iterator.rs:6:1
4 LL | / impl Iterator for Countdown {
7 LL | | fn next(&mut self) -> Option<u8> {
13 = note: `-D clippy::copy-iterator` implied by `-D warnings`
14 = note: consider implementing `IntoIterator` instead
16 error: aborting due to previous error