--- /dev/null
+// Copyright 2017 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.
+
+use iter::FromIterator;
+
+/// Collapses all unit items from an iterator into one.
+///
+/// This is more useful when combined with higher-level abstractions, like
+/// collecting to a `Result<(), E>` where you only care about errors:
+///
+/// ```
+/// use std::io::*;
+/// let data = vec![1, 2, 3, 4, 5];
+/// let res: Result<()> = data.iter()
+/// .map(|x| writeln!(stdout(), "{}", x))
+/// .collect();
+/// assert!(res.is_ok());
+/// ```
+#[stable(feature = "unit_from_iter", since = "1.23.0")]
+impl FromIterator<()> for () {
+ fn from_iter<I: IntoIterator<Item=()>>(iter: I) -> Self {
+ iter.into_iter().for_each(|()| {})
+ }
+}