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.
10 #![warn(clippy::copy_iterator)]
12 #[derive(Copy, Clone)]
15 impl Iterator for Countdown {
18 fn next(&mut self) -> Option<u8> {
19 self.0.checked_sub(1).map(|c| {
27 let my_iterator = Countdown(5);
28 let a: Vec<_> = my_iterator.take(1).collect();
29 assert_eq!(a.len(), 1);
30 let b: Vec<_> = my_iterator.collect();
31 assert_eq!(b.len(), 5);