diff -r 3c00344f49c9 -r f179aa1045a4 lemon/dfs.h
--- a/lemon/dfs.h	Wed Oct 17 19:14:07 2018 +0200
+++ b/lemon/dfs.h	Thu Nov 01 11:27:05 2018 +0100
@@ -1318,7 +1318,7 @@
     template <class T>
     struct SetReachedMapTraits : public Traits {
       typedef T ReachedMap;
-      static ReachedMap *createReachedMap(const Digraph &digraph) {
+      static ReachedMap *createReachedMap(const Digraph &) {
         LEMON_ASSERT(false, "ReachedMap is not initialized");
         return 0; // ignore warnings
       }