diff -r 1309a803a057 -r a30455cd0107 lemon/dfs.h
--- a/lemon/dfs.h	Wed Jan 11 13:58:30 2012 +0100
+++ b/lemon/dfs.h	Fri Jan 20 19:16:43 2012 +0100
@@ -1191,6 +1191,7 @@
         visitor.backtrack(arc);
       }
       _Visitor& visitor;
+      Constraints() {}
     };
   };
 #endif