diff -r ee581a0ecfbf -r b873350e6258 lemon/concepts/heap.h
--- a/lemon/concepts/heap.h	Fri Jan 06 16:27:06 2012 +0100
+++ b/lemon/concepts/heap.h	Thu Jan 19 15:25:06 2012 +0100
@@ -252,6 +252,7 @@
 
         _Heap& heap;
         ItemIntMap& map;
+        Constraints() {}
       };
     };