1 files changed, 6 insertions, 0 deletions
diff --git a/src/expr/node_value.h b/src/expr/node_value.h
index 9f8a8f45b..3c21777ed 100644
--- a/src/expr/node_value.h
+++ b/src/expr/node_value.h
@@ -144,6 +144,12 @@ private:
   class iterator {
     const_nv_iterator d_i;
   public:
+    typedef T value_type;
+    typedef ptrdiff_t difference_type;
+    typedef T* pointer;
+    typedef T& reference;
+
+    iterator() : d_i(NULL) {}
     explicit iterator(const_nv_iterator i) : d_i(i) {}
 
     inline T operator*();