From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 337603858427; Wed, 27 Mar 2024 14:03:46 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 337603858427 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1711548226; bh=t+STrsU1kdfNrKBKY7d3cgJRndvfBRlo4izufoTSUFI=; h=From:To:Subject:Date:In-Reply-To:References:From; b=ge6lvaU3DYHx0fv6rd8BmUS3ogxkCsexO9lPWSOl6MiJ9NjMaUdnnqCp5F1FbIWlp YwpLCd6GRdgbU0V4Jfx3W3BPjifgKSD474KPH5GwANKRBEZWXPrLvtod7rFe8XYDvG GGbKtkwGvlNqoEemnJvBCGsQ6rLKtOQwJNMnRSkc= From: "redi at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/100667] [11/12/13/14 Regression] std::tuple cannot be constructed from A&&, if A not defined (only forward declared) Date: Wed, 27 Mar 2024 14:03:45 +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: 11.1.0 X-Bugzilla-Keywords: 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: P2 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 11.5 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 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D100667 --- Comment #9 from Jonathan Wakely --- The changes in https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1285r0.pdf mean t= hat it's only undefined if the result of is_constructible_v would change were T completed. So there's no benefit to enforcing the completeness requirement here, it's not UB anyway.=