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From: "dev at hrookami dot icu" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/96645] [9/10/11 Regression] std::variant default constructor
Date: Mon, 17 Aug 2020 14:24:28 +0000 [thread overview]
Message-ID: <bug-96645-4-o4BAdzrSTG@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-96645-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96645
--- Comment #2 from Sergey <dev at hrookami dot icu> ---
(In reply to Jonathan Wakely from comment #1)
> This is not a bug in std::variant:
>
>
> template<bool B>
> struct bool_constant
> {
> static constexpr bool value = B;
> using type = bool_constant;
> };
>
> using true_type = bool_constant<true>;
>
> template<typename T>
> struct is_default_constructible
> : bool_constant<__is_constructible(T)>
> { };
>
> void testVarStruct()
> {
> struct DataWithStruct {
> struct A {
> int number = 5; // compiles, if remove initialization
> };
>
> is_default_constructible<A>::type t = true_type{};
> };
> }
>
> v.C: In function 'void testVarStruct()':
> v.C:22:47: error: could not convert 'true_type{}' from 'bool_constant<true>'
> to 'bool_constant<false>'
> 22 | is_default_constructible<A>::type t = true_type{};
> | ^~~~~~~~~~~
> | |
> | bool_constant<true>
>
>
> This stopped working with r269032 which changed the result of the
> __is_constructible built-in.
>
> Clang also rejects this, for the same reason, but EDG accepts it.
Clang compiles it if use libc++ instead of libstdc++
next prev parent reply other threads:[~2020-08-17 14:24 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-17 7:58 [Bug libstdc++/96645] New: " dev at hrookami dot icu
2020-08-17 14:21 ` [Bug c++/96645] [9/10/11 Regression] " redi at gcc dot gnu.org
2020-08-17 14:24 ` dev at hrookami dot icu [this message]
2020-08-17 14:30 ` redi at gcc dot gnu.org
2020-08-17 14:40 ` redi at gcc dot gnu.org
2020-08-18 7:49 ` dev at hrookami dot icu
2020-08-25 10:31 ` rguenth at gcc dot gnu.org
2020-10-12 12:33 ` rguenth at gcc dot gnu.org
2021-01-25 13:53 ` jakub at gcc dot gnu.org
2021-02-15 15:28 ` ppalka at gcc dot gnu.org
2021-04-02 18:20 ` jason at gcc dot gnu.org
2021-04-02 18:21 ` jason at gcc dot gnu.org
2021-04-03 11:27 ` redi at gcc dot gnu.org
2021-06-01 8:18 ` [Bug c++/96645] [9/10/11/12 " rguenth at gcc dot gnu.org
2021-09-06 19:56 ` eyalroz1 at gmx dot com
2021-11-23 17:08 ` redi at gcc dot gnu.org
2022-03-22 14:12 ` [Bug c++/96645] [9/10/11/12 Regression] [CWG2335] std::variant default constructor and unparsed DMI jason at gcc dot gnu.org
2022-03-22 16:15 ` jason at gcc dot gnu.org
2022-03-22 16:22 ` jason at gcc dot gnu.org
2022-03-22 17:31 ` ppalka at gcc dot gnu.org
2022-03-22 20:56 ` eyalroz1 at gmx dot com
2022-03-22 21:29 ` redi at gcc dot gnu.org
2022-03-23 13:36 ` jason at gcc dot gnu.org
2022-03-24 18:31 ` cvs-commit at gcc dot gnu.org
2022-03-26 23:22 ` jason at gcc dot gnu.org
2022-03-31 1:43 ` cvs-commit at gcc dot gnu.org
2022-04-01 14:00 ` cvs-commit at gcc dot gnu.org
2022-04-01 14:07 ` jason at gcc dot gnu.org
2022-04-01 14:14 ` jason at gcc dot gnu.org
2022-04-22 8:26 ` redi at gcc dot gnu.org
2022-05-15 6:35 ` [Bug c++/96645] [9/10/11/12/13 " pinskia at gcc dot gnu.org
2022-08-15 4:53 ` [Bug c++/96645] [10/11/12/13 " pinskia at gcc dot gnu.org
2023-04-26 6:55 ` [Bug c++/96645] [10/11/12/13/14 " rguenth at gcc dot gnu.org
2023-07-27 9:22 ` [Bug c++/96645] [11/12/13/14 " rguenth at gcc dot gnu.org
2024-05-21 9:10 ` [Bug c++/96645] [11/12/13/14/15 " jakub at gcc dot gnu.org
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