From: Ville Voutilainen <ville.voutilainen@gmail.com>
Date: Mon, 19 Dec 2016 15:22:05 +0000 (+0200)
Subject: backport: Make the perfect-forwarding constructor of a two-element tuple sfinae away... 
X-Git-Tag: releases/gcc-5.5.0~633
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=83c65d6de8460954f00d719f299a3e4b3f1a366f;p=thirdparty%2Fgcc.git

backport: Make the perfect-forwarding constructor of a two-element tuple sfinae away when the first argument is an allocator_arg.

Backport from mainline
2016-12-19  Ville Voutilainen  <ville.voutilainen@gmail.com>

Make the perfect-forwarding constructor of a two-element tuple
sfinae away when the first argument is an allocator_arg.
* include/std/tuple (tuple(_U1&&, _U2&&)): Constrain.
* testsuite/20_util/tuple/cons/allocator_with_any.cc: New.

From-SVN: r243797
---

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 8dbed86fd647..c56ff11ba5bf 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,13 @@
+2016-12-19  Ville Voutilainen  <ville.voutilainen@gmail.com>
+
+	Backport from mainline
+	2016-12-19  Ville Voutilainen  <ville.voutilainen@gmail.com>
+
+	Make the perfect-forwarding constructor of a two-element tuple
+	sfinae away when the first argument is an allocator_arg.
+	* include/std/tuple (tuple(_U1&&, _U2&&)): Constrain.
+	* testsuite/20_util/tuple/cons/allocator_with_any.cc: New.
+
 2016-12-13  Jonathan Wakely  <jwakely@redhat.com>
 
 	Backport from mainline
diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple
index e500a762d876..90a0d73c58b6 100644
--- a/libstdc++-v3/include/std/tuple
+++ b/libstdc++-v3/include/std/tuple
@@ -607,7 +607,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       template<typename _U1, typename _U2, typename = typename
 	       enable_if<__and_<is_convertible<_U1, _T1>,
-				is_convertible<_U2, _T2>>::value>::type>
+				is_convertible<_U2, _T2>,
+				__not_<is_same<typename decay<_U1>::type,
+					       allocator_arg_t>>>
+			 ::value>::type>
         explicit
         constexpr tuple(_U1&& __a1, _U2&& __a2)
 	: _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
diff --git a/libstdc++-v3/testsuite/20_util/tuple/cons/allocator_with_any.cc b/libstdc++-v3/testsuite/20_util/tuple/cons/allocator_with_any.cc
new file mode 100644
index 000000000000..dd9a06603ae2
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/tuple/cons/allocator_with_any.cc
@@ -0,0 +1,42 @@
+// { dg-do run }
+// { dg-options "-std=gnu++14" }
+// Copyright (C) 2016 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/>.
+
+
+// NOTE: This makes use of the fact that we know how moveable
+// is implemented on tuple.  If the implementation changed
+// this test may begin to fail.
+
+#include <tuple>
+#include <experimental/any>
+#include <testsuite_hooks.h>
+
+using std::experimental::any;
+
+void test01()
+{
+    std::tuple<any, any> t(std::allocator_arg,
+			   std::allocator<any>{});
+    VERIFY(std::get<0>(t).empty());
+    VERIFY(std::get<1>(t).empty());
+}
+
+int main()
+{
+    test01();
+}