From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id E7D5E3865490; Wed, 22 May 2024 22:01:18 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org E7D5E3865490 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1716415278; bh=Esxh0SjvVqQ8+hObkKY8WwmZCxYEqs/RZLVSjVP4pBs=; h=From:To:Subject:Date:In-Reply-To:References:From; b=vI7aOimUlBjBOa1ZJojQ6WulVWYuDioO7AD3+lC8b1Qvr5hcDLFPXL/0EJ/x4nWLE M0R6iMITzX9IAKtRhprcJUVGN4jjDwhGORskuziIOWD/Zbav0/h7uG1kPCPSkbRlAl eZJS10yNHjnW5nXeoLepHwRyL+XhKxbAsSlTGNBA= From: "s.murthy at outlook dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/115198] Class template argument deduction fails for copy ctor when used with an alias template if the aliased class template has explicitly defaulted copy ctor Date: Wed, 22 May 2024 22:01:18 +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: 14.1.0 X-Bugzilla-Keywords: rejects-valid X-Bugzilla-Severity: normal X-Bugzilla-Who: s.murthy at outlook dot com 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: 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=3D115198 --- Comment #3 from Sean Murthy --- For everyone's convenience, attaching here the compiler's error message. The notes the compiler attached to the error indicate the issue might be with a possibly erroneous/superfluous deduction guide the compiler itself generate= s.=20 At least that is my speculation based on the first note attached to the err= or message. :57:13: error: class template argument deduction failed: 57 | A1 a1(c1); | ^ :57:13: error: call of overloaded 'C1(C1&)' is ambiguous :5:7: note: candidate: 'C1(C1)-> C1 [with T =3D= int]' 5 | class C1 | ^~ :9:5: note: candidate: 'C1(const C1&)-> C1 [wit= h T =3D int]' 9 | C1(const C1& other) =3D default;=