libstdc++/68276 consistently qualify std::forward

	PR libstdc++/68276
	* include/std/functional (__invoke_impl, _Mem_fn::operator()): Qualify
	std::forward.
	testsuite/20_util/function_objects/mem_fn/68276.cc: New.

From-SVN: r231879

libstdc++-v3/ChangeLog

+2015-12-21  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/68276
+	* include/std/functional (__invoke_impl, _Mem_fn::operator()): Qualify
+	std::forward.
+	testsuite/20_util/function_objects/mem_fn/68276.cc: New.
+
 2015-12-21  Ville Voutilainen  <ville.voutilainen@gmail.com>
 
 	PR libstdc++/66693

libstdc++-v3/include/std/functional

@@ -221,15 +221,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     inline _Res
     __invoke_impl(__invoke_memfun_ref, _MemFun&& __f, _Tp&& __t,
 		  _Args&&... __args)
-    noexcept(noexcept((__invfwd<_Tp>(__t).*__f)(forward<_Args>(__args)...)))
-    { return (__invfwd<_Tp>(__t).*__f)(forward<_Args>(__args)...); }
+    noexcept(noexcept(
+	  (__invfwd<_Tp>(__t).*__f)(std::forward<_Args>(__args)...)))
+    { return (__invfwd<_Tp>(__t).*__f)(std::forward<_Args>(__args)...); }
 
   template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
     inline _Res
     __invoke_impl(__invoke_memfun_deref, _MemFun&& __f, _Tp&& __t,
 		  _Args&&... __args)
-    noexcept(noexcept(((*forward<_Tp>(__t)).*__f)(forward<_Args>(__args)...)))
-    { return ((*forward<_Tp>(__t)).*__f)(forward<_Args>(__args)...); }
+    noexcept(noexcept(
+	  ((*std::forward<_Tp>(__t)).*__f)(std::forward<_Args>(__args)...)))
+    {
+      return ((*std::forward<_Tp>(__t)).*__f)(std::forward<_Args>(__args)...);
+    }
 
   template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
     inline _Res
@@ -241,8 +245,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     inline _Res
     __invoke_impl(__invoke_memobj_deref, _MemFun&& __f, _Tp&& __t,
 		  _Args&&... __args)
-    noexcept(noexcept((*forward<_Tp>(__t)).*__f))
-    { return (*forward<_Tp>(__t)).*__f; }
+    noexcept(noexcept((*std::forward<_Tp>(__t)).*__f))
+    { return (*std::forward<_Tp>(__t)).*__f; }
 
   /// Invoke a callable object.
   template<typename _Callable, typename... _Args>
@@ -603,8 +607,9 @@ _GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
       template<typename... _Args>
 	auto
 	operator()(_Args&&... __args) const
-	noexcept(noexcept(std::__invoke(_M_pmf, forward<_Args>(__args)...)))
-	-> decltype(std::__invoke(_M_pmf, forward<_Args>(__args)...))
+	noexcept(noexcept(
+	      std::__invoke(_M_pmf, std::forward<_Args>(__args)...)))
+	-> decltype(std::__invoke(_M_pmf, std::forward<_Args>(__args)...))
 	{ return std::__invoke(_M_pmf, std::forward<_Args>(__args)...); }
     };
 
@@ -627,7 +632,7 @@ _GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
       template<typename _Tp>
 	auto
 	operator()(_Tp&& __obj) const
-	noexcept(noexcept(std::__invoke(_M_pm, forward<_Tp>(__obj))))
+	noexcept(noexcept(std::__invoke(_M_pm, std::forward<_Tp>(__obj))))
 	-> decltype(std::__invoke(_M_pm, std::forward<_Tp>(__obj)))
 	{ return std::__invoke(_M_pm, std::forward<_Tp>(__obj)); }
     };

libstdc++-v3/testsuite/20_util/function_objects/mem_fn/68276.cc

+// Copyright (C) 2015 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++11" }
+// { dg-do compile }
+
+#include <functional>
+
+namespace n
+{
+  template<typename T> struct identity { using type = T; };
+
+  template<typename T>
+    T&&
+    forward(typename identity<T>::type& t)
+    { return static_cast<T&&>(t); }
+
+  struct X { };
+}
+
+struct server
+{
+  void action(n::X) { }
+
+  void act() {
+    auto f = std::mem_fn(&server::action);
+    n::X x;
+    f(this, x);
+  }
+};
+