1Index: include/std/type_traits
2===================================================================
3--- include/std/type_traits	(revision 185724)
4+++ include/std/type_traits	(working copy)
5@@ -1746,7 +1746,7 @@
6
7   template<typename _Tp, typename _Up>
8     struct common_type<_Tp, _Up>
9-    { typedef decltype(true ? declval<_Tp>() : declval<_Up>()) type; };
10+    { typedef typename decay<decltype(true ? declval<_Tp>() : declval<_Up>())>::type type; };
11
12   template<typename _Tp, typename _Up, typename... _Vp>
13     struct common_type<_Tp, _Up, _Vp...>
14