2 files changed, 2 insertions, 2 deletions
diff --git a/src/expr/node.h b/src/expr/node.h
index 372eec8c0..999719592 100644
--- a/src/expr/node.h
+++ b/src/expr/node.h
@@ -612,7 +612,7 @@ public:
 
   public:
     typedef NodeTemplate<ref_count> value_type;
-    typedef ptrdiff_t difference_type;
+    typedef std::ptrdiff_t difference_type;
     typedef NodeTemplate<ref_count>* pointer;
     typedef NodeTemplate<ref_count>& reference;
 
diff --git a/src/expr/node_value.h b/src/expr/node_value.h
index 1722bae30..f2da42731 100644
--- a/src/expr/node_value.h
+++ b/src/expr/node_value.h
@@ -152,7 +152,7 @@ private:
   public:
     typedef std::random_access_iterator_tag iterator_category;
     typedef T value_type;
-    typedef ptrdiff_t difference_type;
+    typedef std::ptrdiff_t difference_type;
     typedef T* pointer;
     typedef T& reference;