Add FromIterator impl

src/default_hashmap.rs

@@ -690,6 +690,21 @@ where
     keys: Vec<K>,
 }
 
+impl<K, V, S> FromIterator<(K, V)> for DefaultHashMap<K, V, S>
+where
+    K: Eq + Hash,
+    V: Default,
+    S: BuildHasher + Default,
+{
+    fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> Self {
+        let mut map = DefaultHashMap::with_hasher(Default::default());
+        for (k, v) in iter {
+            let _ = map.insert(k, v);
+        }
+        map
+    }
+}
+
 #[macro_export]
 /// A quick way to instantiate a HashMap.
 ///

tests/test_hashmap.rs

@@ -362,6 +362,16 @@ fn into_iter_default_hashmap() {
     assert_eq!(v, correct_v);
 }
 
+#[test]
+fn from_iter_hashmap() {
+    let data = [(1, 1), (2, 2), (3, 3), (4, 4)];
+    let map: DefaultHashMap<i8, u8> = data.iter().cloned().collect();
+
+    let correct_map: DefaultHashMap<i8, u8> = defaulthashmap!((1, 1), (2, 2), (3, 3), (4, 4));
+
+    assert_eq!(map, correct_map);
+}
+
 #[test]
 fn borrow_loop_over_default_hashmap() {
     let mut map: DefaultHashMap<i8, u8> = DefaultHashMap::new();