Checkpoint

src/util/scoped_map.rs

@@ -5,6 +5,12 @@ pub struct ScopedMap<K: Eq + Hash + PartialEq, V> {
     scopes: Vec<HashMap<K, V>>,
 }
 
+impl<K: Eq + Hash + PartialEq, V> Default for ScopedMap<K, V> {
+    fn default() -> Self {
+        ScopedMap::new()
+    }
+}
+
 impl<K: Eq + Hash + PartialEq, V> ScopedMap<K, V> {
     /// Generate a new scoped map.
     ///