From 4af2cf38f063aa1695fa653b9bb981c7218add47 Mon Sep 17 00:00:00 2001
From: Howard Hinnant <hhinnant@apple.com>
Date: Thu, 1 Nov 2012 16:32:14 +0000
Subject: [PATCH] Richard Smith:  This fixes a problem in std::is_constructible
 for incomplete types, and those types with a user-defined operator,().

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@167233 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/type_traits | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/type_traits b/include/type_traits
index 59b07b326..26c37dfa0 100644
--- a/include/type_traits
+++ b/include/type_traits
@@ -1771,8 +1771,10 @@ class _LIBCPP_VISIBLE result_of<_Fn(_A0, _A1, _A2)>
 
 //      main is_constructible test
 
+template<typename, typename T> struct __select_2nd { typedef T type; };
+
 template <class _Tp, class ..._Args>
-decltype(_VSTD::move(_Tp(_VSTD::declval<_Args>()...)), true_type())
+typename __select_2nd<decltype(_VSTD::move(_Tp(_VSTD::declval<_Args>()...))), true_type>::type
 __is_constructible_test(_Tp&&, _Args&& ...);
 
 template <class ..._Args>