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