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 78CF53858C53; Wed, 29 Mar 2023 20:13:23 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 78CF53858C53
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1680120803;
	bh=aX2iJoIqYoVVgRbcm+cXUKAOCxDuhH5eIv1bPjECa/s=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=nMbFN6wEbfsAhhPdHNtG1oRDp5cj9tlJaqiMTYJsiUCI2UH3psHRzJQg18DYDRxrn
	 6Glh5Ud7rqVmmyxi2v6tjrGEiB9+QP92+GXBVTBldleoTzoqKpJGESX02QNoLyWOU/
	 IGjQKEDX0xI4W3XCfwI9DWPCjFgN++k+yBFhxHZ8=
From: "richard-gccbugzilla at metafoo dot co.uk" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/109337] c++2a test concepts4.C passes when it should fail
Date: Wed, 29 Mar 2023 20:13:23 +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: unknown
X-Bugzilla-Keywords: accepts-invalid
X-Bugzilla-Severity: normal
X-Bugzilla-Who: richard-gccbugzilla at metafoo dot co.uk
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: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cc
Message-ID: <bug-109337-4-KoQbd4Cpcy@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-109337-4@http.gcc.gnu.org/bugzilla/>
References: <bug-109337-4@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=3D109337

Richard Smith <richard-gccbugzilla at metafoo dot co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |richard-gccbugzilla@metafoo
                   |                            |.co.uk

--- Comment #6 from Richard Smith <richard-gccbugzilla at metafoo dot co.uk=
> ---
(In reply to Andrew Pinski from comment #5)
> (In reply to Christopher Di Bella from comment #3)
> > This is apparently a Clang bug: the RHS of `R42c` isn't evaluated becau=
se of
> > short-circuiting. Apologies for the noise and thanks for helping me work
> > through it.
>=20
> No, clang and GCC disagree even on:
> ```
> template <class Ub> concept A42b =3D true;
> template <class Tc> concept R42c =3D A42b<Tc&>;
>=20
> static_assert (R42c<void>);
> ```
>=20
> There is no short-circuting here.

No substitution is performed into 'Tc&' here, because normalization of R42c
produces the atomic constraint 'true' with an empty parameter mapping. So t=
he
type 'void&' is never formed.=