diff --git a/lemon/bits/base_extender.h b/lemon/bits/base_extender.h
--- a/lemon/bits/base_extender.h
+++ b/lemon/bits/base_extender.h
@@ -38,10 +38,10 @@
   // \brief BaseDigraph to BaseGraph extender
   template <typename Base>
   class UndirDigraphExtender : public Base {
+    typedef Base Parent;
 
   public:
 
-    typedef Base Parent;
     typedef typename Parent::Arc Edge;
     typedef typename Parent::Node Node;
 
@@ -280,8 +280,9 @@
 
   template <typename Base>
   class BidirBpGraphExtender : public Base {
+    typedef Base Parent;
+
   public:
-    typedef Base Parent;
     typedef BidirBpGraphExtender Digraph;
 
     typedef typename Parent::Node Node;