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 50DDB384641C; Wed, 24 Apr 2024 21:32:48 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 50DDB384641C
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1713994368;
	bh=A8g9DSp7nE69iU5KSD7Y6M7evp71hq0HGuvItaMKPFo=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=xKSgrtcu8Rdji8uHQwQSHLDRSzJh0RttCFT2oGc5Tcex40lmWa6fAIhTayVqgp2BK
	 PBhNfdRX/YxPsDhXQswNUkzPYsZvHwBgm7FCupMfQzNPgnoKlb1qSEROK/wW3vvWG8
	 4SMEhMbleWMP85i1qNmq7yiO0ZMSxHgEQKqIC7wU=
From: "ppalka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/94061] defaulted member operator <=> defined as deleted if
 a base has protected member operator <=>
Date: Wed, 24 Apr 2024 21:32:47 +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: rejects-valid
X-Bugzilla-Severity: normal
X-Bugzilla-Who: ppalka at gcc dot gnu.org
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-94061-4-eJUoSIqcrR@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-94061-4@http.gcc.gnu.org/bugzilla/>
References: <bug-94061-4@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
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94061

--- Comment #7 from Patrick Palka <ppalka at gcc dot gnu.org> ---
(In reply to Patrick Palka from comment #6)
> It seems reasonable for this to work but there might be a defect, or at
> least lack of clarity, in the standard in this situation.
>=20
> http://eel.is/c++draft/class.spaceship#3 specifies how a defaulted <=3D> =
is
> defined, in terms of <=3D> comparisons of corresponding subobjects.  But =
it's
> not clear how each of these <=3D> comparisons is written.  If they're alw=
ays
> written like operator expressions, e.g. x_i <=3D> y_i then if x_i / y_i a=
re
> base class subobjects that have a protected <=3D>, then such a definition
> would indeed be ill-formed due to the protected access:
> https://godbolt.org/z/5h4ednq9  The <=3D> comparison would need to be wri=
tten
> A::operator<=3D>(b) as mentioned in comment #2 in order for the definitio=
n to
> be valid IIUC?
Oops, the full CE link is https://godbolt.org/z/5h4ednq9E=