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 0F6C53857003; Thu,  3 Dec 2020 19:18:51 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 0F6C53857003
From: "jason at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/96960] [C++20] ICE in tsubst_copy_and_build, at
 cp/pt.c:20531 from lambda in return-type-requirement
Date: Thu, 03 Dec 2020 19:18:50 +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: 11.0
X-Bugzilla-Keywords: ice-on-valid-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: jason 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: cc short_desc
Message-ID: <bug-96960-4-Q6lSURRokM@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-96960-4@http.gcc.gnu.org/bugzilla/>
References: <bug-96960-4@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: <https://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: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Thu, 03 Dec 2020 19:18:51 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D96960

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org
            Summary|ICE in                      |[C++20] ICE in
                   |tsubst_copy_and_build, at   |tsubst_copy_and_build, at
                   |cp/pt.c:20531 from lambda   |cp/pt.c:20531 from lambda
                   |in return-type-requirement  |in return-type-requirement

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> ---
This has to do with type_deducible_p's use of tf_partial.  That function is
left over from the days before P1084; we still kind of treat return type
requirements as deduction rather than simply checking the constraint.  Thou=
gh
other places where we do need to do deduction work properly:

C0<char [([] { return 42; }())]> auto x =3D 42;

int f(C0<char [([] { return 42; }())]> auto x);
int y =3D f(42);=