diff -r 0976225b5cae -r be7dd3a8d6a3 lemon/concepts/heap.h
--- a/lemon/concepts/heap.h	Wed Jan 11 14:01:21 2012 +0100
+++ b/lemon/concepts/heap.h	Fri Jan 20 19:20:02 2012 +0100
@@ -314,6 +314,7 @@
 
         _Heap& heap;
         ItemIntMap& map;
+        Constraints() {}
       };
     };