diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/libcore/iter/traits.rs | 7 | ||||
| -rw-r--r-- | src/test/run-pass/extend-for-unit.rs | 20 |
2 files changed, 27 insertions, 0 deletions
diff --git a/src/libcore/iter/traits.rs b/src/libcore/iter/traits.rs index 173dfc36f04..1551429557f 100644 --- a/src/libcore/iter/traits.rs +++ b/src/libcore/iter/traits.rs @@ -352,6 +352,13 @@ pub trait Extend<A> { fn extend<T: IntoIterator<Item=A>>(&mut self, iter: T); } +#[stable(feature = "extend_for_unit", since = "1.28.0")] +impl Extend<()> for () { + fn extend<T: IntoIterator<Item = ()>>(&mut self, iter: T) { + iter.into_iter().for_each(drop) + } +} + /// An iterator able to yield elements from both ends. /// /// Something that implements `DoubleEndedIterator` has one extra capability diff --git a/src/test/run-pass/extend-for-unit.rs b/src/test/run-pass/extend-for-unit.rs new file mode 100644 index 00000000000..d1a0614bd8a --- /dev/null +++ b/src/test/run-pass/extend-for-unit.rs @@ -0,0 +1,20 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// 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. + +pub fn main() { + let mut x = 0; + { + let iter = (0..5).map(|_| { + x += 1; + }); + ().extend(iter); + } + assert_eq!(x, 5); +} |