From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 213EB3858C2F; Wed, 31 May 2023 15:52:33 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 213EB3858C2F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1685548353; bh=LAk8ENoI0FjEPpQZMgRgMc7yPkPsaTXhjF5qMOz9+To=; h=From:To:Subject:Date:In-Reply-To:References:From; b=QuG53IhoeEjK6Pk4rfdaPE75dwHeDq61O//8GiDt+FKDRVVUc16cfITKMzPF8o2pb miMDTBSmq6b9+js7j920+qsann9HDwNx/qZd2GP0ZIBNO3+/Pyngoc3elXy1CUueG0 MrN1B0gmJwO50IZ0pD8H4Q1HQjX0d1qSDSVtKtFI= From: "f.heckenbach@fh-soft.de" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/92707] type alias on type alias on lambda in unevaluated context does not work Date: Wed, 31 May 2023 15:52:32 +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: 9.2.0 X-Bugzilla-Keywords: c++-lambda, rejects-valid X-Bugzilla-Severity: normal X-Bugzilla-Who: f.heckenbach@fh-soft.de 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 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=3D92707 Frank Heckenbach changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |f.heckenbach@fh-soft.de --- Comment #1 from Frank Heckenbach --- Probably the same bug in a slightly different form: % cat test.cpp template struct S { }; template using A =3D S ; template using B =3D A ; B <0> a; % g++ -std=3Dc++20 -Wall -Wextra test.cpp test.cpp:4:1: error: 'B' does not name a type 4 | B <0> a; | ^ It works when using A instead of B. It works when using an alias for "decltype ([] { })". Other compilers accept it as is. Also, I find the message confusing (even if it was rightly rejected): Of course, 'B' does not name a type. It's followed by template arguments, so '= B' shouldn't be a type, but a template or template alias, or 'B <0>' should be= a type.=