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| -rw-r--r-- | src/libcore/iter.rs | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/libcore/iter.rs b/src/libcore/iter.rs index e3e783329ec..ddc4fb32cde 100644 --- a/src/libcore/iter.rs +++ b/src/libcore/iter.rs @@ -2740,7 +2740,13 @@ pub trait Extend<A> { /// It is important to note that both back and forth work on the same range, /// and do not cross: iteration is over when they meet in the middle. /// +/// In a similar fashion to the [`Iterator`] protocol, once a +/// `DoubleEndedIterator` returns `None` from a `next_back()`, calling it again +/// may or may not ever return `Some` again. `next()` and `next_back()` are +/// interchangable for this purpose. +/// /// [`Iterator`]: trait.Iterator.html +/// /// # Examples /// /// Basic usage: |