Implement RFC 839 for BinaryHeap

Author: jooert

src/libcollections/binary_heap.rs

@@ -760,3 +760,10 @@ impl<T: Ord> Extend<T> for BinaryHeap<T> {
         }
     }
 }
+
+#[unstable(feature = "extend_ref", reason = "recently added")]
+impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BinaryHeap<T> {
+    fn extend<I: IntoIterator<Item=&'a T>>(&mut self, iter: I) {
+        self.extend(iter.into_iter().cloned());
+    }
+}

src/libcollectionstest/binary_heap.rs

@@ -217,3 +217,28 @@ fn test_drain() {
 
     assert!(q.is_empty());
 }
+
+#[test]
+fn test_extend_ref() {
+    let mut a = BinaryHeap::new();
+    a.push(1);
+    a.push(2);
+
+    a.extend(&[3, 4, 5]);
+
+    assert_eq!(a.len(), 5);
+    assert_eq!(a.into_sorted_vec(), [1, 2, 3, 4, 5]);
+
+    let mut a = BinaryHeap::new();
+    a.push(1);
+    a.push(2);
+    let mut b = BinaryHeap::new();
+    b.push(3);
+    b.push(4);
+    b.push(5);
+
+    a.extend(&b);
+
+    assert_eq!(a.len(), 5);
+    assert_eq!(a.into_sorted_vec(), [1, 2, 3, 4, 5]);
+}