diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index 9109a730cce..570e657b101 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -716,6 +716,14 @@ impl<I: Iterator + ?Sized> Iterator for Box<I> {
         (**self).nth(n)
     }
 }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator + Sized> Iterator for Box<I> {
+    fn last(self) -> Option<I::Item> where I: Sized {
+        (*self).last()
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<I: DoubleEndedIterator + ?Sized> DoubleEndedIterator for Box<I> {
     fn next_back(&mut self) -> Option<I::Item> {
diff --git a/src/liballoc/collections/binary_heap.rs b/src/liballoc/collections/binary_heap.rs
index c898f064fd0..9f531f5b83c 100644
--- a/src/liballoc/collections/binary_heap.rs
+++ b/src/liballoc/collections/binary_heap.rs
@@ -1035,6 +1035,11 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
+
+    #[inline]
+    fn last(self) -> Option<&'a T> {
+        self.iter.last()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/liballoc/collections/btree/map.rs b/src/liballoc/collections/btree/map.rs
index 6b079fc87cc..8e1c870cf6b 100644
--- a/src/liballoc/collections/btree/map.rs
+++ b/src/liballoc/collections/btree/map.rs
@@ -1193,6 +1193,10 @@ impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.length, Some(self.length))
     }
+
+    fn last(mut self) -> Option<(&'a K, &'a V)> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
@@ -1253,6 +1257,10 @@ impl<'a, K: 'a, V: 'a> Iterator for IterMut<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.length, Some(self.length))
     }
+
+    fn last(mut self) -> Option<(&'a K, &'a mut V)> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1421,6 +1429,10 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
+
+    fn last(mut self) -> Option<&'a K> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1458,6 +1470,10 @@ impl<'a, K, V> Iterator for Values<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
+
+    fn last(mut self) -> Option<&'a V> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1495,6 +1511,10 @@ impl<'a, K, V> Iterator for Range<'a, K, V> {
             unsafe { Some(self.next_unchecked()) }
         }
     }
+
+    fn last(mut self) -> Option<(&'a K, &'a V)> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
@@ -1508,6 +1528,10 @@ impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
+
+    fn last(mut self) -> Option<&'a mut V> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
@@ -1626,6 +1650,10 @@ impl<'a, K, V> Iterator for RangeMut<'a, K, V> {
             unsafe { Some(self.next_unchecked()) }
         }
     }
+
+    fn last(mut self) -> Option<(&'a K, &'a mut V)> {
+        self.next_back()
+    }
 }
 
 impl<'a, K, V> RangeMut<'a, K, V> {
diff --git a/src/liballoc/collections/btree/set.rs b/src/liballoc/collections/btree/set.rs
index 16a96ca19b8..d3af910a82c 100644
--- a/src/liballoc/collections/btree/set.rs
+++ b/src/liballoc/collections/btree/set.rs
@@ -1019,6 +1019,9 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
+    fn last(mut self) -> Option<&'a T> {
+        self.next_back()
+    }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
@@ -1073,6 +1076,10 @@ impl<'a, T> Iterator for Range<'a, T> {
     fn next(&mut self) -> Option<&'a T> {
         self.iter.next().map(|(k, _)| k)
     }
+
+    fn last(mut self) -> Option<&'a T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "btree_range", since = "1.17.0")]
diff --git a/src/liballoc/collections/linked_list.rs b/src/liballoc/collections/linked_list.rs
index 40a82d6feaa..b5dbbe8fe2d 100644
--- a/src/liballoc/collections/linked_list.rs
+++ b/src/liballoc/collections/linked_list.rs
@@ -832,6 +832,11 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.len, Some(self.len))
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -881,6 +886,11 @@ impl<'a, T> Iterator for IterMut<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.len, Some(self.len))
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a mut T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/liballoc/collections/vec_deque.rs b/src/liballoc/collections/vec_deque.rs
index 71faf672962..573dd86b23a 100644
--- a/src/liballoc/collections/vec_deque.rs
+++ b/src/liballoc/collections/vec_deque.rs
@@ -2206,6 +2206,11 @@ impl<'a, T> Iterator for Iter<'a, T> {
         self.tail = self.head - iter.len();
         final_res
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -2319,6 +2324,11 @@ impl<'a, T> Iterator for IterMut<'a, T> {
         accum = front.iter_mut().fold(accum, &mut f);
         back.iter_mut().fold(accum, &mut f)
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a mut T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index 7f7722548f5..1b0d3c19692 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -2385,6 +2385,11 @@ impl Iterator for Drain<'_> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
+
+    #[inline]
+    fn last(mut self) -> Option<char> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
diff --git a/src/libcore/ascii.rs b/src/libcore/ascii.rs
index c0ab364380f..e6a6fdde540 100644
--- a/src/libcore/ascii.rs
+++ b/src/libcore/ascii.rs
@@ -117,6 +117,7 @@ impl Iterator for EscapeDefault {
     type Item = u8;
     fn next(&mut self) -> Option<u8> { self.range.next().map(|i| self.data[i]) }
     fn size_hint(&self) -> (usize, Option<usize>) { self.range.size_hint() }
+    fn last(mut self) -> Option<u8> { self.next_back() }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl DoubleEndedIterator for EscapeDefault {
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 34f2d8917ea..f3fbf351817 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -1333,6 +1333,11 @@ impl<'a> Iterator for Lines<'a> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.0.size_hint()
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a str> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -4241,6 +4246,11 @@ impl<'a> Iterator for SplitWhitespace<'a> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a str> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "split_whitespace", since = "1.1.0")]
@@ -4267,6 +4277,11 @@ impl<'a> Iterator for SplitAsciiWhitespace<'a> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a str> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "split_ascii_whitespace", since = "1.34.0")]