From 3a4964aef37d746a78d88b632c49290dda824108 Mon Sep 17 00:00:00 2001
From: Marshall Clow <mclow.lists@gmail.com>
Date: Tue, 14 Apr 2015 13:53:53 +0000
Subject: [PATCH] Qualify an internal call in is_assignable to prevent ADL
 lookup, which would 'complete' an type definition unnecessarily. Thanks to
 Richard Smith for the report.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@234886 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/type_traits                                         | 2 +-
 .../meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp  | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/type_traits b/include/type_traits
index aad94256..1b2c63e3 100644
--- a/include/type_traits
+++ b/include/type_traits
@@ -1533,7 +1533,7 @@ template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::va
 struct __is_assignable_imp
     : public common_type
         <
-            decltype(__is_assignable_test(declval<_Tp>(), declval<_Arg>()))
+            decltype(_VSTD::__is_assignable_test(declval<_Tp>(), declval<_Arg>()))
         >::type {};
 
 template <class _Tp, class _Arg>
diff --git a/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp b/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp
index b46a4d6b..d33019bc 100644
--- a/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp
+++ b/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp
@@ -49,6 +49,9 @@ struct E
 };
 #endif
 
+template <typename T>
+struct X { T t; };
+
 int main()
 {
     test_is_assignable<int&, int&> ();
@@ -67,4 +70,7 @@ int main()
     test_is_not_assignable<void, const void> ();
     test_is_not_assignable<const void, const void> ();
     test_is_not_assignable<int(), int> ();
+    
+//  pointer to incomplete template type
+	test_is_assignable<X<D>*&, X<D>*> ();
 }