From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id BB1083858027; Fri, 22 Jul 2022 16:53:55 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org BB1083858027 From: "cvs-commit at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/106320] [10 regression] build failure (due to view requirement changes?) Date: Fri, 22 Jul 2022 16:53:55 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: libstdc++ X-Bugzilla-Version: 10.4.0 X-Bugzilla-Keywords: rejects-valid X-Bugzilla-Severity: normal X-Bugzilla-Who: cvs-commit at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: ppalka at gcc dot gnu.org X-Bugzilla-Target-Milestone: 10.5 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Jul 2022 16:53:55 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106320 --- Comment #6 from CVS Commits --- The releases/gcc-11 branch has been updated by Patrick Palka : https://gcc.gnu.org/g:36dd51bf87e1c533bf33ad3b16fd3fe06c356746 commit r11-10170-g36dd51bf87e1c533bf33ad3b16fd3fe06c356746 Author: Patrick Palka Date: Fri Jul 22 12:52:03 2022 -0400 libstdc++: Fix backward compatibility of P2325R3 backport [PR106320] The 11 and 10 partial backports of P2325R3, r11-9555-g92d612cccc1eec and r10-10808-g22b86cdc4d7fdd, unnecessarily preserved some changes from the paper that made certain view specializations no longer default constructible, changes which aren't required to reap the overall benefi= ts of the paper and which are backward incompatible with pre-P2325R3 code = in practice. This patch reverts the problematic changes, specifically it relaxes the constraints on various views' default constructors added by the paper so that we keep only the constraints that were already implicitly imposed by the NSDMIs of the view. Thus for example this patch retains the default_initializable<_Vp> constraint on transform_view's default constructor since its '_Vp _M_base =3D _Vp()' NSDMI already requires th= is constraint, and it removes the default_initializable<_Fp> constraint since the corresponding member '__detail::__box<_Fp> _M_fun' doesn't require default constructibility (specializations of __box are always default constructible). After reverting these changes, all static_asserts from p2325.cc that verify lack of default constructibility now fail as expected, matching the pre-P2325R3 behavior. PR libstdc++/106320 libstdc++-v3/ChangeLog: * include/std/ranges (single_view): Relax constraints on default constructor so as to preserve pre-P2325R3 behavior. (filter_view): Likewise. (transform_view): Likewise. (take_while_view): Likewise. (drop_while_view): Likewise. * testsuite/std/ranges/adaptors/join.cc (test13): New test. * testsuite/std/ranges/p2325.cc: Fix S to be only non default constructible and not also non copy constructible. XFAIL the tests that verify a non default constructible functor makes a view non default constructible (lines 94, 97 and 98). XFAIL the test that effectively verifies a non default constructible element type makes single_view non default constructible (line 114).=