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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/100667] [11/12/13/14 Regression] std::tuple<A&&> cannot be constructed from A&&, if A not defined (only forward declared)
Date: Wed, 27 Mar 2024 17:44:37 +0000 [thread overview]
Message-ID: <bug-100667-4-0ioMLxthgz@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-100667-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100667
--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #8)
> But I think it would be best to fix it in the compiler, so that we always
> allow directly binding T&& or const T& to T, even if T is incomplete.
> Otherwise we'll be playing whackamole all over the library.
Actually the workarounds would only be needed in <type_traits>:
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -1187,6 +1187,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
"template argument must be a complete class or an unbounded array");
};
+ template<typename _Tp, typename _Up>
+ struct is_nothrow_constructible<_Tp&, _Up>
+ : __is_nothrow_constructible_impl<_Tp&, __add_rval_ref_t<_Up>>
+ { };
+
+ template<typename _Tp, typename _Up>
+ struct is_nothrow_constructible<_Tp&&, _Up>
+ : __is_nothrow_constructible_impl<_Tp&&, __add_rval_ref_t<_Up>>
+ { };
+
/// is_nothrow_default_constructible
template<typename _Tp>
struct is_nothrow_default_constructible
@@ -1496,7 +1506,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_convertible)
template<typename _From, typename _To>
struct is_convertible
- : public __bool_constant<__is_convertible(_From, _To)>
+ : public __bool_constant<__is_convertible(__add_rval_ref_t<_From>, _To)>
{ };
#else
template<typename _From, typename _To,
@@ -1547,7 +1557,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
/// is_nothrow_convertible_v
template<typename _From, typename _To>
inline constexpr bool is_nothrow_convertible_v
- = __is_nothrow_convertible(_From, _To);
+ = __is_nothrow_convertible(__add_rval_ref_t<_From>, _To);
/// is_nothrow_convertible
template<typename _From, typename _To>
I think this should be OK but I haven't tested it yet.
next prev parent reply other threads:[~2024-03-27 17:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-19 8:00 [Bug libstdc++/100667] New: " piotrwn1 at gmail dot com
2021-05-19 9:09 ` [Bug libstdc++/100667] [11/12 Regression] " redi at gcc dot gnu.org
2021-06-18 7:56 ` ostash at ostash dot kiev.ua
2021-07-28 7:07 ` rguenth at gcc dot gnu.org
2022-04-21 7:49 ` rguenth at gcc dot gnu.org
2023-05-29 10:05 ` [Bug libstdc++/100667] [11/12/13/14 " jakub at gcc dot gnu.org
2023-05-29 11:16 ` piotrwn1 at gmail dot com
2024-03-27 12:59 ` redi at gcc dot gnu.org
2024-03-27 13:36 ` redi at gcc dot gnu.org
2024-03-27 14:02 ` redi at gcc dot gnu.org
2024-03-27 14:03 ` redi at gcc dot gnu.org
2024-03-27 14:14 ` redi at gcc dot gnu.org
2024-03-27 17:44 ` redi at gcc dot gnu.org [this message]
2024-03-28 18:26 ` cvs-commit at gcc dot gnu.org
2024-03-28 22:33 ` [Bug libstdc++/100667] [11/12/13 " redi at gcc dot gnu.org
2024-05-01 20:31 ` cvs-commit at gcc dot gnu.org
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