Index: boost/concept/detail/msvc.hpp
===================================================================
--- boost/concept/detail/msvc.hpp	(revision 49619)
+++ boost/concept/detail/msvc.hpp	(working copy)
@@ -32,6 +32,9 @@
     virtual void failed(Model* x)
     {
         x->~Model();
+#if BOOST_WORKAROUND(BOOST_MSVC, == 1500)
+        ignore_unused_variable_warning(x);
+#endif
     }
 };
 # endif