From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 3C3913858D39; Mon,  1 May 2023 11:23:36 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 3C3913858D39
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1682940216;
	bh=lGwLosSghnwrPvhjU5Roa540Sneg6px8xtP8IXzlzw4=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=TwICtA5zuEmGNIPCa2gddxuBjYb8zaRh8k5FLsSrD+53AoVVIn2YwmVy41g8Ye3yN
	 yC+wUx79e8pDlkNvCV2HQky5sj7BqscNmUXjpaCFkArup3dGgp5W9rGGjYnaAJaP3g
	 RaIKuSMWlOrccrefxgpa8UioL01TpOWTJ3YgvjQs=
From: "ali.mpfard at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/109683] [13/14 Regression] False cyclic dependency error
 reported for constraint
Date: Mon, 01 May 2023 11:23:35 +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: 13.1.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: ali.mpfard at gmail dot com
X-Bugzilla-Status: UNCONFIRMED
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: <bug-109683-4-g3ulK8MFgE@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-109683-4@http.gcc.gnu.org/bugzilla/>
References: <bug-109683-4@http.gcc.gnu.org/bugzilla/>
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: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109683

Ali Mohammad Pur Fard <ali.mpfard at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ali.mpfard at gmail dot com

--- Comment #1 from Ali Mohammad Pur Fard <ali.mpfard at gmail dot com> ---
As a note, using a type alias for `T` in the constraint seems to work around
the issue:
```
template <typename T, typename>
struct VariantConstructors {
  using U =3D T;
  VariantConstructors(T&& t)
    requires(requires { U(t); });
};

// Everything below is the same as the repro case

template <typename... Ts>
struct InheritFromEntries : Ts... {};

template <typename... Ps>
struct InheritFromPack: InheritFromEntries<Ps>... {
  using InheritFromEntries<Ps>::InheritFromEntries...;
};

template <typename... Ts>
struct Variant : InheritFromPack<VariantConstructors<Ts, Variant<Ts...>>...>
{};

template <typename T>
class Outer;
struct Inner {
    Inner(Outer<int>);
};
template<typename T>
class Outer {
    Variant<T, Inner> value_;
};

struct Empty {};
void fn(Outer<Empty> x) {}
```

(https://godbolt.org/z/1GTrjcvG6)=