Implement RFC 839 for VecMap

Author: jooert

src/libcollections/vec_map.rs

@@ -828,6 +828,13 @@ impl<V> Extend<(usize, V)> for VecMap<V> {
     }
 }
 
+#[unstable(feature = "extend_ref", reason = "recently added")]
+impl<'a, V: Copy> Extend<(usize, &'a V)> for VecMap<V> {
+    fn extend<I: IntoIterator<Item=(usize, &'a V)>>(&mut self, iter: I) {
+        self.extend(iter.into_iter().map(|(key, &value)| (key, value)));
+    }
+}
+
 impl<V> Index<usize> for VecMap<V> {
     type Output = V;
 

src/libcollectionstest/vec_map.rs

@@ -493,6 +493,22 @@ fn test_entry(){
     assert_eq!(map.len(), 6);
 }
 
+#[test]
+fn test_extend_ref() {
+    let mut a = VecMap::new();
+    a.insert(1, "one");
+    let mut b = VecMap::new();
+    b.insert(2, "two");
+    b.insert(3, "three");
+
+    a.extend(&b);
+
+    assert_eq!(a.len(), 3);
+    assert_eq!(a[&1], "one");
+    assert_eq!(a[&2], "two");
+    assert_eq!(a[&3], "three");
+}
+
 mod bench {
     use std::collections::VecMap;