From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 27EE83857022; Thu, 1 Apr 2021 22:04:09 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 27EE83857022 From: "jason at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/99599] [11 Regression] Concepts requirement falsely reporting cyclic dependency, breaks tag_invoke pattern Date: Thu, 01 Apr 2021 22:04:08 +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: rejects-valid X-Bugzilla-Severity: normal X-Bugzilla-Who: jason at gcc dot gnu.org X-Bugzilla-Status: SUSPENDED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 11.0 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: everconfirmed bug_status cf_reconfirmed_on 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: Thu, 01 Apr 2021 22:04:09 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99599 Jason Merrill changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Status|UNCONFIRMED |SUSPENDED Last reconfirmed| |2021-04-01 --- Comment #2 from Jason Merrill --- (In reply to the_gamester28 from comment #0) > It seems that the template requirements of invoke_tag(bar_tag, int) are > considered while evaluating line marked "here". Requirements of irrelevant > overloads should not be considered, as it can potentially lead to falsely > reporting a cyclic dependency. This is as specified by http://wg21.link/cwg2369 I think it would be reasonable to allow a compiler to accept the testcase u= nder a generalization of 13.9.1/9: "If the function selected by overload resolut= ion (12.4) can be determined without instantiating a class template definition,= it is unspecified whether that instantiation actually takes place." But that does not require a compiler to accept it. It might make sense to check non-dependent conversions that don't require template instantiation, then constraints, then non-dependent conversions th= at do require template instantiation. But that's a matter for the committee; = G++ is conforming to the current working paper.=