diff --git a/include/stack b/include/stack
index 30909c1..2992b09 100644
--- a/include/stack
+++ b/include/stack
@@ -91,7 +91,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Tp, class _Container> class _LIBCPP_TYPE_VIS_ONLY stack;
+template <class _Tp, class _Container = deque<_Tp> > class _LIBCPP_TYPE_VIS_ONLY stack;
 
 template <class _Tp, class _Container>
 _LIBCPP_INLINE_VISIBILITY
@@ -103,7 +103,7 @@
 bool
 operator< (const stack<_Tp, _Container>& __x, const stack<_Tp, _Container>& __y);
 
-template <class _Tp, class _Container = deque<_Tp> >
+template <class _Tp, class _Container /*= deque<_Tp>*/>
 class _LIBCPP_TYPE_VIS_ONLY stack
 {
 public: