diff -r c160bf9f18ef -r 580af8cf2f6a lemon/bits/map_extender.h
--- a/lemon/bits/map_extender.h	Thu Nov 05 10:01:02 2009 +0100
+++ b/lemon/bits/map_extender.h	Thu Nov 05 10:23:16 2009 +0100
@@ -49,6 +49,8 @@
     typedef typename Parent::Reference Reference;
     typedef typename Parent::ConstReference ConstReference;
 
+    typedef typename Parent::ReferenceMapTag ReferenceMapTag;
+
     class MapIt;
     class ConstMapIt;
 
@@ -191,6 +193,8 @@
     typedef typename Parent::Reference Reference;
     typedef typename Parent::ConstReference ConstReference;
 
+    typedef typename Parent::ReferenceMapTag ReferenceMapTag;
+
     class MapIt;
     class ConstMapIt;