1 // Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution.
4 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
5 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
7 // option. This file may not be copied, modified, or distributed
8 // except according to those terms.
13 #![warn(clippy::copy_iterator)]
15 #[derive(Copy, Clone)]
18 impl Iterator for Countdown {
21 fn next(&mut self) -> Option<u8> {
22 self.0.checked_sub(1).map(|c| {
30 let my_iterator = Countdown(5);
31 let a: Vec<_> = my_iterator.take(1).collect();
32 assert_eq!(a.len(), 1);
33 let b: Vec<_> = my_iterator.collect();
34 assert_eq!(b.len(), 5);