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From: "ppalka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/110853] [c++-concepts] Bad interaction between deduction guide with decay and constraints
Date: Mon, 07 Aug 2023 14:08:18 +0000	[thread overview]
Message-ID: <bug-110853-4-4BbpFOma2d@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-110853-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110853

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |ppalka at gcc dot gnu.org

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Since as you mention a member function body is a complete-class context,
libstdc++'s std::pair implementation strategy does seem non-conforming in this
case.

Clang seems to not propagate constructor constraints to the implicit deduction
guide, according to the following example, and is probably the reason why it
accepts your reduced example.

template<class T>
struct A {
  A(T) requires false; // #1
  A(...); // #2
};

auto a = A(0); // GCC rejects, Clang incorrectly(?) selects #2 with T=int.

      reply	other threads:[~2023-08-07 14:08 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-30 14:05 [Bug c++/110853] New: " daniel.kruegler at googlemail dot com
2023-08-07 14:08 ` ppalka at gcc dot gnu.org [this message]

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