From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-406706-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 26305 invoked by alias); 15 Nov 2012 04:46:39 -0000
Received: (qmail 26266 invoked by uid 48); 15 Nov 2012 04:46:22 -0000
From: "ai.azuma at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/55335] New: [DR 5] cv-qualifiers of destination type in copy-initialization
Date: Thu, 15 Nov 2012 04:46:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: ai.azuma at gmail dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields:
Message-ID: <bug-55335-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2012-11/txt/msg01368.txt.bz2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55335

             Bug #: 55335
           Summary: [DR 5] cv-qualifiers of destination type in
                    copy-initialization
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: ai.azuma@gmail.com


Created attachment 28694
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28694
Output of -v option and preprocessed file with GCC 4.8.0 20121111

The following valid code is rejected by GCC 4.6.4 20121109, 4.7.3 20121110 and
4.8.0 20121111.

/////////////////////////
struct C{};

struct A {
  A(const A&){};
  A(const C&){};
};

int main()
{
  C c;
  const volatile A a = c;
}
/////////////////////////

For the above code, GCC 4.8.0 20121111 complains as follows;

main.cpp: In function 'int main()':
main.cpp:11:24: error: no matching function for call to 'A::A(const volatile
A)'
   const volatile A a = c;
                        ^
main.cpp:11:24: note: candidates are:
main.cpp:5:3: note: A::A(const C&)
   A(const C&){};
   ^
main.cpp:5:3: note:   no known conversion for argument 1 from 'const volatile
A' to 'const C&'
main.cpp:4:3: note: A::A(const A&)
   A(const A&){};
   ^
main.cpp:4:3: note:   no known conversion for argument 1 from 'const volatile
A' to 'const A&'

As far as I can guess from the error message, GCC does not seem to implement
the proposed resolution of DR 5.
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#5