rust-clippy/tests/ui/copy_iterator.rs
2018-10-11 12:16:22 +02:00

35 lines
901 B
Rust

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