Add Ord trait bound on impl Clone for BTreeMap and BTreeSet

Author: crgl

src/liballoc/collections/btree/map.rs

@@ -135,7 +135,7 @@ unsafe impl<#[may_dangle] K, #[may_dangle] V> Drop for BTreeMap<K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> {
+impl<K: Clone + Ord, V: Clone> Clone for BTreeMap<K, V> {
     fn clone(&self) -> BTreeMap<K, V> {
         fn clone_subtree<'a, K: Clone, V: Clone>(
             node: node::NodeRef<marker::Immut<'a>, K, V, marker::LeafOrInternal>

src/liballoc/collections/btree/set.rs

@@ -56,12 +56,23 @@ use super::Recover;
 ///     println!("{}", book);
 /// }
 /// ```
-#[derive(Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
+#[derive(Hash, PartialEq, Eq, Ord, PartialOrd)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct BTreeSet<T> {
     map: BTreeMap<T, ()>,
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone + Ord> Clone for BTreeSet<T> {
+    fn clone(&self) -> Self {
+        BTreeSet { map: self.map.clone() }
+    }
+
+    fn clone_from(&mut self, other: &Self) {
+        self.map.clone_from(&other.map);
+    }
+}
+
 /// An iterator over the items of a `BTreeSet`.
 ///
 /// This `struct` is created by the [`iter`] method on [`BTreeSet`].