Adjust Index/IndexMut impls. For generic collections, we take

references. For collections whose keys are integers, we take both
references and by-value.

1 files changed, 20 insertions, 4 deletions

diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index 9139e182ce4..86664d7eb0c 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -1088,7 +1088,7 @@ impl<K, V, S> HashMap<K, V, S>
     ///     Some(x) => *x = "b",
     ///     None => (),
     /// }
-    /// assert_eq!(map[1], "b");
+    /// assert_eq!(map[&1], "b");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V>
@@ -1111,7 +1111,7 @@ impl<K, V, S> HashMap<K, V, S>
     ///
     /// map.insert(37, "b");
     /// assert_eq!(map.insert(37, "c"), Some("b"));
-    /// assert_eq!(map[37], "c");
+    /// assert_eq!(map[&37], "c");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn insert(&mut self, k: K, v: V) -> Option<V> {
@@ -1244,6 +1244,7 @@ impl<K, V, S> Default for HashMap<K, V, S>
     }
 }
 
+#[cfg(stage0)]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<K, Q: ?Sized, V, S> Index<Q> for HashMap<K, V, S>
     where K: Eq + Hash + Borrow<Q>,
@@ -1258,6 +1259,21 @@ impl<K, Q: ?Sized, V, S> Index<Q> for HashMap<K, V, S>
     }
 }
 
+#[cfg(not(stage0))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, K, Q: ?Sized, V, S> Index<&'a Q> for HashMap<K, V, S>
+    where K: Eq + Hash + Borrow<Q>,
+          Q: Eq + Hash,
+          S: HashState,
+{
+    type Output = V;
+
+    #[inline]
+    fn index(&self, index: &Q) -> &V {
+        self.get(index).expect("no entry found for key")
+    }
+}
+
 /// HashMap iterator.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Iter<'a, K: 'a, V: 'a> {
@@ -2185,7 +2201,7 @@ mod test_map {
         map.insert(2, 1);
         map.insert(3, 4);
 
-        assert_eq!(map[2], 1);
+        assert_eq!(map[&2], 1);
     }
 
     #[test]
@@ -2197,7 +2213,7 @@ mod test_map {
         map.insert(2, 1);
         map.insert(3, 4);
 
-        map[4];
+        map[&4];
     }
 
     #[test]