From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-patches-return-413714-listarch-gcc-patches=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 103999 invoked by alias); 11 Nov 2015 22:18:05 -0000
Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-patches.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>
List-Post: <mailto:gcc-patches@gcc.gnu.org>
List-Help: <mailto:gcc-patches-help@gcc.gnu.org>
Sender: gcc-patches-owner@gcc.gnu.org
Received: (qmail 103978 invoked by uid 89); 11 Nov 2015 22:18:04 -0000
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2
X-Spam-User: qpsmtpd, 2 recipients
X-HELO: mx1.redhat.com
Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Wed, 11 Nov 2015 22:18:03 +0000
Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22])	by mx1.redhat.com (Postfix) with ESMTPS id 29BFFC03E4;	Wed, 11 Nov 2015 22:18:02 +0000 (UTC)
Received: from localhost (ovpn-116-102.ams2.redhat.com [10.36.116.102])	by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id tABMI1Mh024814;	Wed, 11 Nov 2015 17:18:01 -0500
Date: Wed, 11 Nov 2015 22:18:00 -0000
From: Jonathan Wakely <jwakely@redhat.com>
To: Ville Voutilainen <ville.voutilainen@gmail.com>
Cc: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,        libstdc++ <libstdc++@gcc.gnu.org>
Subject: Re: [v3 PATCH] Implement D0013R2, logical type traits.
Message-ID: <20151111221800.GU2937@redhat.com>
References: <CAFk2RUZn0w2JCd4wCpzrCY4GFf=i1mzCdaTQgpAvGiKyakntJw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Disposition: inline
In-Reply-To: <CAFk2RUZn0w2JCd4wCpzrCY4GFf=i1mzCdaTQgpAvGiKyakntJw@mail.gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
User-Agent: Mutt/1.5.24 (2015-08-30)
X-SW-Source: 2015-11/txt/msg01430.txt.bz2

On 12/11/15 00:06 +0200, Ville Voutilainen wrote:
>--- a/gcc/testsuite/g++.dg/cpp0x/Wattributes1.C
>+++ b/gcc/testsuite/g++.dg/cpp0x/Wattributes1.C
>@@ -5,4 +5,4 @@
> #include <new>
> __attribute__((visibility("hidden")))void*operator new(std::size_t); // { dg-warning "visibility attribute ignored" }
>
>-// { dg-message "previous declaration" "" { target *-*-* } 111 }
>+// { dg-message "previous declaration" "" { target *-*-* } 116 }
>diff --git a/libstdc++-v3/include/experimental/type_traits b/libstdc++-v3/include/experimental/type_traits
>index b0ed3b0..b7f3bda 100644
>--- a/libstdc++-v3/include/experimental/type_traits
>+++ b/libstdc++-v3/include/experimental/type_traits
>@@ -271,6 +271,28 @@ template<typename _To, template<typename...> class _Op, typename... _Args>
>   constexpr bool is_detected_convertible_v
>     = is_detected_convertible<_To, _Op, _Args...>::value;
>
>+#if __cplusplus > 201402L
>+
>+#define __cpp_lib_experimental_logical_traits 201511
>+
>+using std::conjunction;
>+using std::disjunction;
>+using std::negation;

It's unfortunate if the std::experimental versions are only available
for C++17 mode, because the whole point of putting it into both C++17
and the TS was that users can make us of the std::experimental
versions sooner than they can make use of C++17 version. If both
versions depend on using -std=c++17 then the TS versions are entirely
redundant.

So I think we want to define them again, independently, in
<experimental/type_traits>, even though it might lead to ambiguities
for code that does:

using namespace std;
using namespace std::experimental;