From ebd0e4f1996053c1d63709b169682ee8586ae65f Mon Sep 17 00:00:00 2001
From: Will Speak <lithiumflame@gmail.com>
Date: Mon, 18 Sep 2017 07:38:32 +0100
Subject: [PATCH] Add Example of `IntoIterator` as Trait Bound to Docs

Part of #44600.
---
 src/libcore/iter/traits.rs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/libcore/iter/traits.rs b/src/libcore/iter/traits.rs
index 2af129a67bddf..7ef50396c82bf 100644
--- a/src/libcore/iter/traits.rs
+++ b/src/libcore/iter/traits.rs
@@ -196,6 +196,23 @@ pub trait FromIterator<A>: Sized {
 ///     assert_eq!(i as i32, n);
 /// }
 /// ```
+///
+/// It is common to use `IntoIterator` as a trait bound. This allows
+/// the input collection type to change, so long as it is still an
+/// iterator. Additional bounds can be specified by restricting on
+/// `Item`:
+///
+/// ```rust
+/// fn collect_as_strings<T>(collection: T) -> Vec<String>
+///     where T: IntoIterator,
+///           T::Item : std::fmt::Debug,
+/// {
+///     collection
+///         .into_iter()
+///         .map(|item| format!("{:?}", item))
+///         .collect()
+/// }
+/// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait IntoIterator {
     /// The type of the elements being iterated over.