collections: Implement Ord for DList, RingBuf, TreeMap, TreeSet

src/libcollections/dlist.rs

@@ -691,6 +691,13 @@ impl<A: PartialOrd> PartialOrd for DList<A> {
     }
 }
 
+impl<A: Ord> Ord for DList<A> {
+    #[inline]
+    fn cmp(&self, other: &DList<A>) -> Ordering {
+        iter::order::cmp(self.iter(), other.iter())
+    }
+}
+
 impl<A: Clone> Clone for DList<A> {
     fn clone(&self) -> DList<A> {
         self.iter().map(|x| x.clone()).collect()

src/libcollections/ringbuf.rs

@@ -460,6 +460,13 @@ impl<A: PartialOrd> PartialOrd for RingBuf<A> {
     }
 }
 
+impl<A: Ord> Ord for RingBuf<A> {
+    #[inline]
+    fn cmp(&self, other: &RingBuf<A>) -> Ordering {
+        iter::order::cmp(self.iter(), other.iter())
+    }
+}
+
 impl<S: Writer, A: Hash<S>> Hash<S> for RingBuf<A> {
     fn hash(&self, state: &mut S) {
         self.len().hash(state);

src/libcollections/treemap.rs

@@ -182,6 +182,13 @@ impl<K: Ord, V: PartialOrd> PartialOrd for TreeMap<K, V> {
     }
 }
 
+impl<K: Ord, V: Ord> Ord for TreeMap<K, V> {
+    #[inline]
+    fn cmp(&self, other: &TreeMap<K, V>) -> Ordering {
+        iter::order::cmp(self.iter(), other.iter())
+    }
+}
+
 impl<K: Ord + Show, V: Show> Show for TreeMap<K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(f, "{{"));
@@ -1021,6 +1028,13 @@ impl<T: Ord> PartialOrd for TreeSet<T> {
     }
 }
 
+impl<T: Ord> Ord for TreeSet<T> {
+    #[inline]
+    fn cmp(&self, other: &TreeSet<T>) -> Ordering {
+        iter::order::cmp(self.iter(), other.iter())
+    }
+}
+
 impl<T: Ord + Show> Show for TreeSet<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(f, "{{"));