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 D9EE8382DE11; Wed, 26 Oct 2022 16:32:52 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D9EE8382DE11
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1666801972;
	bh=uW7NlPPFKHOJ9VuR407ffdsBsSxB51L7tjYjGaUErHU=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=afNxHrxqcGQdfNvt8G7vPOGDtE9gniUYcrO389JcE1jeypXpfhE2UDazQ2qGludKC
	 PypC+2scwBzWI4sDmwySHsNAtw+juloNRrrMP5g2gnC1GpVvepGLdQJoyJtpLSt+U9
	 ww1YwB6nIJ5BBtaqDkTPofEMLV9axS1Ah9roQzHw=
From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/107417] g++ fails to recognize parameter pack in
 requires-expression
Date: Wed, 26 Oct 2022 16:32:52 +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: accepts-invalid, rejects-valid
X-Bugzilla-Severity: normal
X-Bugzilla-Who: redi 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: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_status keywords everconfirmed
 cf_reconfirmed_on
Message-ID: <bug-107417-4-k9OPP5Zpwj@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-107417-4@http.gcc.gnu.org/bugzilla/>
References: <bug-107417-4@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=3D107417

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
           Keywords|                            |accepts-invalid,
                   |                            |rejects-valid
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-10-26

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think the underlying issue is that it accepts the pack without expansion:

template<typename... T>
  requires (requires (T x) { x; })
  auto func(T...) { }

And so the error about "no unexpanded parameter packs" is correct, the AST
doesn't contain any. But it should do, the requires-expression is a pack
expression that must be expanded (e.g. in a fold expression).=