[libcxx-commits] [libcxx] 3573065 - [libcxx] Put `std::monostate` in `<utility>` (#128373)
via libcxx-commits
libcxx-commits at lists.llvm.org
Tue Mar 25 10:32:00 PDT 2025
Author: Amr Hesham
Date: 2025-03-25T18:31:57+01:00
New Revision: 357306572d4734a75e649284b4808299d0aba9c8
URL: https://github.com/llvm/llvm-project/commit/357306572d4734a75e649284b4808299d0aba9c8
DIFF: https://github.com/llvm/llvm-project/commit/357306572d4734a75e649284b4808299d0aba9c8.diff
LOG: [libcxx] Put `std::monostate` in `<utility>` (#128373)
Fixes: #127874
Added:
libcxx/test/std/utilities/utility/utility.monostate.relpos/relops.pass.cpp
libcxx/test/std/utilities/utility/utility.monostate/monostate.pass.cpp
Modified:
libcxx/docs/ReleaseNotes/21.rst
libcxx/docs/Status/Cxx2cPapers.csv
libcxx/include/utility
libcxx/test/libcxx/transitive_includes/cxx26.csv
Removed:
################################################################################
diff --git a/libcxx/docs/ReleaseNotes/21.rst b/libcxx/docs/ReleaseNotes/21.rst
index f67a5fced6fc5..877aa06f8b7e4 100644
--- a/libcxx/docs/ReleaseNotes/21.rst
+++ b/libcxx/docs/ReleaseNotes/21.rst
@@ -44,6 +44,7 @@ Implemented Papers
- P2255R2: A type trait to detect reference binding to temporary (implemented the type traits only) (`Github <https://github.com/llvm/llvm-project/issues/105180>`__)
- P2562R1: ``constexpr`` Stable Sorting (`Github <https://github.com/llvm/llvm-project/issues/105360>`__)
- P1222R4: A Standard ``flat_set`` is partially implemented and ``flat_set`` is provided (`Github <https://github.com/llvm/llvm-project/issues/105193>`__)
+- P0472R3: Put std::monostate in <utility> (`Github <https://github.com/llvm/llvm-project/issues/127874>`__)
Improvements and New Features
-----------------------------
diff --git a/libcxx/docs/Status/Cxx2cPapers.csv b/libcxx/docs/Status/Cxx2cPapers.csv
index 9a4cd3e57e842..0cc41d2058dd5 100644
--- a/libcxx/docs/Status/Cxx2cPapers.csv
+++ b/libcxx/docs/Status/Cxx2cPapers.csv
@@ -102,7 +102,7 @@
"`P3475R2 <https://wg21.link/P3475R2>`__","Defang and deprecate ``memory_order::consume``","2025-02 (Hagenberg)","","",""
"`P2786R13 <https://wg21.link/P2786R13>`__","Trivial Relocatability For C++26","2025-02 (Hagenberg)","","",""
"`P3137R3 <https://wg21.link/P3137R3>`__","``views::to_input``","2025-02 (Hagenberg)","","",""
-"`P0472R3 <https://wg21.link/P0472R3>`__","Put ``std::monostate`` in ``<utility>``","2025-02 (Hagenberg)","","",""
+"`P0472R3 <https://wg21.link/P0472R3>`__","Put ``std::monostate`` in ``<utility>``","2025-02 (Hagenberg)","|Complete|","21",""
"`P3349R1 <https://wg21.link/P3349R1>`__","Converting contiguous iterators to pointers","2025-02 (Hagenberg)","","",""
"`P3372R3 <https://wg21.link/P3372R3>`__","constexpr containers and adaptors","2025-02 (Hagenberg)","","",""
"`P3378R2 <https://wg21.link/P3378R2>`__","constexpr exception types","2025-02 (Hagenberg)","","",""
diff --git a/libcxx/include/utility b/libcxx/include/utility
index fb8a6f81350be..bc4eaf6a0cd02 100644
--- a/libcxx/include/utility
+++ b/libcxx/include/utility
@@ -279,6 +279,10 @@ template <class T>
# include <__utility/unreachable.h>
# endif
+# if _LIBCPP_STD_VER >= 26
+# include <__variant/monostate.h>
+# endif
+
# include <version>
// standard-mandated includes
diff --git a/libcxx/test/libcxx/transitive_includes/cxx26.csv b/libcxx/test/libcxx/transitive_includes/cxx26.csv
index c79badd3fa78f..ce8f0261f2b27 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx26.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx26.csv
@@ -301,6 +301,7 @@ experimental/type_traits type_traits
experimental/type_traits version
experimental/utility compare
experimental/utility cstdint
+experimental/utility cstring
experimental/utility initializer_list
experimental/utility limits
experimental/utility utility
@@ -1127,6 +1128,7 @@ unordered_set tuple
unordered_set version
utility compare
utility cstdint
+utility cstring
utility initializer_list
utility limits
utility version
diff --git a/libcxx/test/std/utilities/utility/utility.monostate.relpos/relops.pass.cpp b/libcxx/test/std/utilities/utility/utility.monostate.relpos/relops.pass.cpp
new file mode 100644
index 0000000000000..0f67360de7dbc
--- /dev/null
+++ b/libcxx/test/std/utilities/utility/utility.monostate.relpos/relops.pass.cpp
@@ -0,0 +1,47 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: std-at-least-c++26
+
+// <utility>
+
+// constexpr bool operator<(monostate, monostate) noexcept { return false; }
+// constexpr bool operator>(monostate, monostate) noexcept { return false; }
+// constexpr bool operator<=(monostate, monostate) noexcept { return true; }
+// constexpr bool operator>=(monostate, monostate) noexcept { return true; }
+// constexpr bool operator==(monostate, monostate) noexcept { return true; }
+// constexpr bool operator!=(monostate, monostate) noexcept { return false; }
+// constexpr strong_ordering operator<=>(monostate, monostate) noexcept { return strong_ordering::equal; } // since C++20
+
+#include <cassert>
+#include <utility>
+
+#include "test_comparisons.h"
+#include "test_macros.h"
+
+constexpr bool test() {
+ using M = std::monostate;
+ constexpr M m1{};
+ constexpr M m2{};
+ assert(testComparisons(m1, m2, /*isEqual*/ true, /*isLess*/ false));
+ AssertComparisonsAreNoexcept<M>();
+
+#if TEST_STD_VER > 17
+ assert(testOrder(m1, m2, std::strong_ordering::equal));
+ AssertOrderAreNoexcept<M>();
+#endif // TEST_STD_VER > 17
+
+ return true;
+}
+
+int main(int, char**) {
+ test();
+ static_assert(test());
+
+ return 0;
+}
diff --git a/libcxx/test/std/utilities/utility/utility.monostate/monostate.pass.cpp b/libcxx/test/std/utilities/utility/utility.monostate/monostate.pass.cpp
new file mode 100644
index 0000000000000..ca4c120ff6f68
--- /dev/null
+++ b/libcxx/test/std/utilities/utility/utility.monostate/monostate.pass.cpp
@@ -0,0 +1,31 @@
+
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: std-at-least-c++26
+
+// <utility>
+
+// struct monostate {};
+
+#include <type_traits>
+#include <utility>
+
+#include "test_macros.h"
+
+int main(int, char**) {
+ using M = std::monostate;
+ static_assert(std::is_trivially_default_constructible<M>::value, "");
+ static_assert(std::is_trivially_copy_constructible<M>::value, "");
+ static_assert(std::is_trivially_copy_assignable<M>::value, "");
+ static_assert(std::is_trivially_destructible<M>::value, "");
+ constexpr M m{};
+ ((void)m);
+
+ return 0;
+}
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