diff --git a/src/object/inheritance.cpp b/src/object/inheritance.cpp
index b7258f8e..659b98f9 100644
--- a/src/object/inheritance.cpp
+++ b/src/object/inheritance.cpp
@@ -35,6 +35,7 @@ namespace boost {
 namespace
 {
   enum edge_cast_t { edge_cast = 8010 };
+  template <class T> inline void unused_variable(const T&) { }
 }
 
 // Install properties
@@ -215,7 +216,7 @@ namespace
 
       vertex_t v = add_vertex(full_graph().topology());
       vertex_t v2 = add_vertex(up_graph().topology());
-      (void)v2; // prevent unused var warning on non-debug compile
+      unused_variable(v2);
       assert(v == v2);
       return type_index().insert(p, boost::make_tuple(type, v, dynamic_id_function(0)));
   }