diff --git a/STL_Extension/include/CGAL/iterator.h b/STL_Extension/include/CGAL/iterator.h
index dc3b5dc12b6..968c9e92f13 100644
--- a/STL_Extension/include/CGAL/iterator.h
+++ b/STL_Extension/include/CGAL/iterator.h
@@ -595,8 +595,8 @@ public:
   Join_input_iterator_1() {}
   Join_input_iterator_1(const Join_input_iterator_1& it)
     : i1(it.i1), op(it.op) {}
-  Join_input_iterator_1(I1 i1,const Op& op=Op())
-    : i1(i1), op(op) {}
+  Join_input_iterator_1(I1 i,const Op& o=Op())
+    : i1(i), op(o) {}
   
   I1 current_iterator1() const { return i1; }