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From: Jonathan Wakely <redi@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r11-7743] libstdc++: Add std::is_scoped_enum for C++23 Date: Fri, 19 Mar 2021 20:11:09 +0000 (GMT) [thread overview] Message-ID: <20210319201109.0D8683857C60@sourceware.org> (raw) https://gcc.gnu.org/g:b8ecdc772703729b75fba8b4bb94acfcb6f7cfae commit r11-7743-gb8ecdc772703729b75fba8b4bb94acfcb6f7cfae Author: Jonathan Wakely <jwakely@redhat.com> Date: Fri Mar 19 19:42:18 2021 +0000 libstdc++: Add std::is_scoped_enum for C++23 Implement this C++23 feature, as proposed by P1048R1. This implementation assumes that a C++23 compiler supports concepts already. I don't see any point in using preprocessor hacks to detect compilers which define __cplusplus to a post-C++20 value but don't support concepts yet. libstdc++-v3/ChangeLog: * include/std/type_traits (is_scoped_enum): Define. * include/std/version (__cpp_lib_is_scoped_enum): Define. * testsuite/20_util/is_scoped_enum/value.cc: New test. * testsuite/20_util/is_scoped_enum/version.cc: New test. Diff: --- libstdc++-v3/include/std/type_traits | 17 ++++++ libstdc++-v3/include/std/version | 1 + .../testsuite/20_util/is_scoped_enum/value.cc | 62 ++++++++++++++++++++++ .../testsuite/20_util/is_scoped_enum/version.cc | 27 ++++++++++ 4 files changed, 107 insertions(+) diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits index ad2672d36a6..eeab1ca65fc 100644 --- a/libstdc++-v3/include/std/type_traits +++ b/libstdc++-v3/include/std/type_traits @@ -3279,6 +3279,23 @@ template <typename _From, typename _To> inline constexpr bool is_unbounded_array_v = is_unbounded_array<_Tp>::value; +#if __cplusplus > 202002L +#define __cpp_lib_is_scoped_enum 202011L + + template<typename _Tp> + struct is_scoped_enum + : false_type + { }; + + template<typename _Tp> requires __is_enum(_Tp) + struct is_scoped_enum<_Tp> + : __not_<is_convertible<_Tp, __underlying_type(_Tp)>>::type + { }; + + template<typename _Tp> + inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value; +#endif // C++23 + #ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED #define __cpp_lib_is_constant_evaluated 201811L diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version index e9eca06a72a..cb25148fca5 100644 --- a/libstdc++-v3/include/std/version +++ b/libstdc++-v3/include/std/version @@ -259,6 +259,7 @@ #if __cplusplus > 202002L // c++2b +#define __cpp_lib_is_scoped_enum 202011L #define __cpp_lib_string_contains 202011L #define __cpp_lib_to_underlying 202102L #endif // C++2b diff --git a/libstdc++-v3/testsuite/20_util/is_scoped_enum/value.cc b/libstdc++-v3/testsuite/20_util/is_scoped_enum/value.cc new file mode 100644 index 00000000000..bab7263ae4a --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/is_scoped_enum/value.cc @@ -0,0 +1,62 @@ +// Copyright (C) 2021 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +// { dg-options "-std=gnu++23" } +// { dg-do compile { target c++23 } } + +#include <type_traits> + +#ifndef __cpp_lib_is_scoped_enum +# error "Feature test macro for is_scoped_enum is missing in <type_traits>" +#elif __cpp_lib_is_scoped_enum < 202011L +# error "Feature test macro for is_scoped_enum has wrong value in <type_traits>" +#endif + +#include <testsuite_tr1.h> + +template<typename T> + concept Is_scoped_enum + = __gnu_test::test_category<std::is_scoped_enum, T>(true); + +void +test01() +{ + enum class E { e1, e2 }; + static_assert( Is_scoped_enum<E> ); + enum class Ec : char { e1, e2 }; + static_assert( Is_scoped_enum<Ec> ); + + // negative tests + enum U { u1, u2 }; + static_assert( ! Is_scoped_enum<U> ); + enum F : int { f1, f2 }; + static_assert( ! Is_scoped_enum<F> ); + struct S { }; + static_assert( ! Is_scoped_enum<S> ); + + static_assert( ! Is_scoped_enum<int> ); + static_assert( ! Is_scoped_enum<int[]> ); + static_assert( ! Is_scoped_enum<int[2]> ); + static_assert( ! Is_scoped_enum<int[][2]> ); + static_assert( ! Is_scoped_enum<int[2][3]> ); + static_assert( ! Is_scoped_enum<int*> ); + static_assert( ! Is_scoped_enum<int&> ); + static_assert( ! Is_scoped_enum<int*&> ); + static_assert( ! Is_scoped_enum<int()> ); + static_assert( ! Is_scoped_enum<int(*)()> ); + static_assert( ! Is_scoped_enum<int(&)()> ); +} diff --git a/libstdc++-v3/testsuite/20_util/is_scoped_enum/version.cc b/libstdc++-v3/testsuite/20_util/is_scoped_enum/version.cc new file mode 100644 index 00000000000..ed78fce5fbe --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/is_scoped_enum/version.cc @@ -0,0 +1,27 @@ +// Copyright (C) 2021 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +// { dg-options "-std=gnu++23" } +// { dg-do compile { target c++23 } } + +#include <version> + +#ifndef __cpp_lib_is_scoped_enum +# error "Feature test macro for is_scoped_enum is missing in <version>" +#elif __cpp_lib_is_scoped_enum < 202011L +# error "Feature test macro for is_scoped_enum has wrong value in <version>" +#endif
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