diff -r 4bb9e72e1a41 -r 7fdaa05a69a1 lemon/concepts/heap.h
--- a/lemon/concepts/heap.h	Wed Sep 12 17:25:48 2012 +0200
+++ b/lemon/concepts/heap.h	Thu Sep 13 11:56:19 2012 +0200
@@ -314,6 +314,7 @@
 
         _Heap& heap;
         ItemIntMap& map;
+        Constraints() {}
       };
     };