diff -r 15cf1fd6a505 -r 24bf4b8299e7 lemon/bits/graph_extender.h
--- a/lemon/bits/graph_extender.h	Mon Dec 19 16:59:05 2005 +0000
+++ b/lemon/bits/graph_extender.h	Wed Dec 21 08:47:38 2005 +0000
@@ -474,9 +474,7 @@
 	Parent::nextDown(edge);
       } else {
 	Parent::nextUp(edge);
-	if (edge == INVALID) {
-	  edge.forward = true;
-	}	
+        edge.forward = static_cast<UndirEdge&>(edge) == INVALID;
       }
     }
 
@@ -494,9 +492,7 @@
 	Parent::nextUp(edge);
       } else {
 	Parent::nextDown(edge);
-	if (edge == INVALID) {
-	  edge.forward = true;
-	}	
+	edge.forward = static_cast<UndirEdge&>(edge) == INVALID;
       }
     }