[Bug c++/63540] Erroneous "'Derived' declares a move constructor or move assignment operator" in error.

["danregister at poczta dot fm" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63540

Daniel Adamski <danregister at poczta dot fm> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |danregister at poczta dot fm

--- Comment #2 from Daniel Adamski <danregister at poczta dot fm> ---
I have another variant of that issue:
----------------------------------------------------------------
struct Base
{
    Base() {}
    Base(const Base &) {}
    Base & operator=(Base &&) { return *this; }
};
struct D1 : Base
{
    using Base::operator=;
    D1 & operator=(const D1&) { return *this; }
};

int main()
{
    D1 x;
    D1 y = x;
    (void) y;
}
----------------------------------------------------------------

The error:
----------------------------------------------------------------
test.cpp: In function ‘int main()’:
test.cpp:19:12: error: use of deleted function ‘D1::D1(const D1&)’
     D1 y = x;
            ^
test.cpp:10:8: note: ‘D1::D1(const D1&)’ is implicitly declared as deleted
because ‘D1’ declares a move constructor or move assignment operator
 struct D1 : Base
----------------------------------------------------------------

It's enough to remove one of the lines (any one) from D1 for the error to go
away.

Yet another variant:
----------------------------------------------------------------
struct Base
{
    Base() {}
    Base(const Base &) {}
    Base & operator=(Base &&) { return *this; }
};
struct D1 : Base
{
    using Base::operator=;
};
struct D2 : D1
{
    D2 & operator=(const D2 &) { return *this; }
};

int main()
{
    D1 x;
    D1 y = x;
    (void) y;
}
----------------------------------------------------------------

The error is the same. The "operator=()" in "D2" doesn't have to be D2's
assignment operator. It may some other "operator()", e.g., "operator(int)" or
it may be "using D1::operator=;" or "using Base::operator=;"
>From gcc-bugs-return-484753-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Mon Apr 27 16:03:46 2015
Return-Path: <gcc-bugs-return-484753-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Delivered-To: listarch-gcc-bugs@gcc.gnu.org
Received: (qmail 77671 invoked by alias); 27 Apr 2015 16:03:46 -0000
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
Delivered-To: mailing list gcc-bugs@gcc.gnu.org
Received: (qmail 77627 invoked by uid 48); 27 Apr 2015 16:03:42 -0000
From: "mpolacek at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/65901] no warning or error for va_arg (ap, void)
Date: Mon, 27 Apr 2015 16:03:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c
X-Bugzilla-Version: 6.0
X-Bugzilla-Keywords:
X-Bugzilla-Severity: minor
X-Bugzilla-Who: mpolacek at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution:
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 6.0
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields: bug_status cf_reconfirmed_on cc target_milestone everconfirmed
Message-ID: <bug-65901-4-pWcK7CStvf@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-65901-4@http.gcc.gnu.org/bugzilla/>
References: <bug-65901-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2015-04/txt/msg02305.txt.bz2
Content-length: 676

https://gcc.gnu.org/bugzilla/show_bug.cgi?ide901

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-04-27
                 CC|                            |mpolacek at gcc dot gnu.org
   Target Milestone|---                         |6.0
     Ever confirmed|0                           |1

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
We should probably reject such a program.  G++/clang reject that as well.