[committed] libstdc++: Add std::is_scoped_enum for C++23
Jonathan Wakely
jwakely@redhat.com
Fri Mar 19 20:11:37 GMT 2021
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.
Tested powerpc64le-linux. Committed to trunk.
-------------- next part --------------
commit b8ecdc772703729b75fba8b4bb94acfcb6f7cfae
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Fri Mar 19 19:42:18 2021
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 --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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