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 0953A3858C56; Tue,  4 Oct 2022 19:34:26 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 0953A3858C56
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1664912067;
	bh=G4qx3wtFwIugzUI9ZTNvUCui9GC0S+G2NzYVgnShETQ=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=d3stjSibS3Mzh9KUw1ean4324gUj6jcGGPu9PXGwb++F9/pIHMK3uk2ccG5gOfI0/
	 kVufW3wCYChk/2427YXx4DdQG78EB4T3qeI4Pz0luC4tF7ZBidZhyHS2mi3LnSTH/6
	 yNnEPVNZP46uAk7iIcQWQqBSIeVYCyNPqaGJGrPQ=
From: "mpolacek at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/107085] __reference_constructs_from_temporary does not
 detect static up-cast
Date: Tue, 04 Oct 2022 19:34:26 +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: 13.0
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: mpolacek at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: mpolacek at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-107085-4-WPa6OGI9vH@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-107085-4@http.gcc.gnu.org/bugzilla/>
References: <bug-107085-4@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=3D107085

--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
(In reply to Roy Jacobson from comment #3)
> Thanks! But a Base const& is still not detected:
>=20
> static_assert(__reference_constructs_from_temporary(Base const&, Derived)=
);
>=20
> And in this case I think it _is_ a bug that this doesn't compile?

To make sure I understand this correctly, __reference_constructs_from_tempo=
rary
should say "yes" here, because it's just like

  const Base& b(Derived{});

where we bind 'b' to the Base subobject of a temporary Derived object, yes?=