diff -r 959d78f3fe0e -r 2236d00ca778 lemon/concepts/graph_components.h
--- a/lemon/concepts/graph_components.h	Wed Oct 17 22:56:43 2018 +0200
+++ b/lemon/concepts/graph_components.h	Thu Nov 01 19:49:51 2018 +0100
@@ -103,6 +103,7 @@
           _GraphItem i1;
           i1=INVALID;
           _GraphItem i2 = i1;
+          ::lemon::ignore_unused_variable_warning(i2);
           _GraphItem i3 = INVALID;
 
           i1 = i2 = i3;
@@ -734,6 +735,7 @@
           ++(++it1);
 
           Item bi = it1;
+          ::lemon::ignore_unused_variable_warning(bi);
           bi = it2;
         }
         const GR& g;
@@ -824,6 +826,7 @@
           ++it2 = it1;
           ++(++it1);
           Item e = it1;
+          ::lemon::ignore_unused_variable_warning(e);
           e = it2;
         }
         const Base& node;