From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
 id 9A9663840C33; Tue,  9 Jun 2020 14:52:25 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9A9663840C33
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
 s=default; t=1591714345;
 bh=Ty3TCEg7Ug5fJBTVXL3OPPriGTJbKxruWXngh+DccPo=;
 h=From:To:Subject:Date:In-Reply-To:References:From;
 b=bzSWL6cCekwJgxlmL752ntCtUq5ropXCGyzd5qJxTB6adQL5AOpgWg8p4kz1ffoUR
 QZwngcgBjPjSgBkYuAL/ExPfeoG46bjggK9YvUBqbRj4NnkoCzf1LLJiCYW8T5rD25
 vrzu230M8cj9ijF0VJ+M8Lnjnc0UF0zBSlYojq+M=
From: "barry.revzin at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/95567] Defaulted virtual <=> has the wrong behavior
Date: Tue, 09 Jun 2020 14:52:25 +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: 10.0
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: barry.revzin at gmail dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-95567-4-YdV1TeUnuB@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-95567-4@http.gcc.gnu.org/bugzilla/>
References: <bug-95567-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <http://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <http://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Tue, 09 Jun 2020 14:52:25 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D95567

--- Comment #1 from Barry Revzin <barry.revzin at gmail dot com> ---
To follow up on this, it's not the operator<=3D> being virtual that's signi=
ficant
but rather the class itself being polymorphic. This exhibits the same behav=
ior:

#include <compare>

struct B {
  B(int i) : i(i) {}
  VIRTUAL ~B() =3D default;

  std::strong_ordering operator<=3D>(B const& other) const =3D default;
  int i;
};

struct D : B {
  D(int i, int j) : B(i), j(j) {}
  int j;
};

bool check() {
    return B(2) =3D=3D D(2, 3);
}

https://godbolt.org/z/ZFqB59=