From 246eb897c921e1aee45361d7c10c6fd274cc7f74 Mon Sep 17 00:00:00 2001
From: Marshall Clow <mclow.lists@gmail.com>
Date: Tue, 13 Jun 2017 14:34:58 +0000
Subject: Fix bug 33389 - __is_transparent check requires too much

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@305292 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/__functional_base | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

(limited to 'include/__functional_base')

diff --git a/include/__functional_base b/include/__functional_base
index 0d2c2fc65..79017fe75 100644
--- a/include/__functional_base
+++ b/include/__functional_base
@@ -548,16 +548,13 @@ template <class _Tp> void cref(const _Tp&&) = delete;
 #endif
 
 #if _LIBCPP_STD_VER > 11
-template <class _Tp1, class _Tp2 = void>
-struct __is_transparent
-{
-private:
-    struct __two {char __lx; char __lxx;};
-    template <class _Up> static __two __test(...);
-    template <class _Up> static char __test(typename _Up::is_transparent* = 0);
-public:
-    static const bool value = sizeof(__test<_Tp1>(0)) == 1;
-};
+template <class _Tp, class, class = void>
+struct __is_transparent : false_type {};
+
+template <class _Tp, class _Up>
+struct __is_transparent<_Tp, _Up,  
+                        typename __void_t<typename _Tp::is_transparent>::type>
+   : true_type {};
 #endif
 
 // allocator_arg_t
-- 
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