Add implementations of last in terms of next_back on a bunch of DoubleEndedIterators.

r?Manishearth

1 files changed, 14 insertions, 0 deletions

diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index cd62c3e0524..50bb37b6ed2 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -2385,6 +2385,11 @@ impl<T> Iterator for IntoIter<T> {
     fn count(self) -> usize {
         self.len()
     }
+
+    #[inline]
+    fn last(mut self) -> Option<T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -2504,6 +2509,11 @@ impl<T> Iterator for Drain<'_, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
+
+    #[inline]
+    fn last(mut self) -> Option<T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
@@ -2573,6 +2583,10 @@ impl<I: Iterator> Iterator for Splice<'_, I> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.drain.size_hint()
     }
+
+    fn last(mut self) -> Option<Self::Item> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "vec_splice", since = "1.21.0")]