collections: Add missing Default impls

Add Default impls for TreeMap, TreeSet, SmallIntMap, BitvSet, DList,
PriorityQueue, RingBuf, TrieMap, and TrieSet.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/libcollections/priority_queue.rs b/src/libcollections/priority_queue.rs
index ea3e7d17471..f25864933f2 100644
--- a/src/libcollections/priority_queue.rs
+++ b/src/libcollections/priority_queue.rs
@@ -14,6 +14,7 @@
 
 use core::prelude::*;
 
+use core::default::Default;
 use core::mem::{zeroed, replace, swap};
 use core::ptr;
 
@@ -37,6 +38,11 @@ impl<T: Ord> Mutable for PriorityQueue<T> {
     fn clear(&mut self) { self.data.truncate(0) }
 }
 
+impl<T: Ord> Default for PriorityQueue<T> {
+    #[inline]
+    fn default() -> PriorityQueue<T> { PriorityQueue::new() }
+}
+
 impl<T: Ord> PriorityQueue<T> {
     /// An iterator visiting all values in underlying vector, in
     /// arbitrary order.