P0288

libcxx/docs/FeatureTestMacroTable.rst

@@ -316,7 +316,7 @@ Status
     ------------------------------------------------- -----------------
     ``__cpp_lib_is_scoped_enum``                      ``202011L``
     ------------------------------------------------- -----------------
-    ``__cpp_lib_move_only_function``                  *unimplemented*
+    ``__cpp_lib_move_only_function``                  ``202110L``
     ------------------------------------------------- -----------------
     ``__cpp_lib_optional``                            ``202110L``
     ------------------------------------------------- -----------------

libcxx/docs/Status/Cxx2bPapers.csv

@@ -23,7 +23,7 @@
 "`P2136R3 <https://wg21.link/P2136R3>`__","LWG","invoke_r","June 2021","",""
 "`P2166R1 <https://wg21.link/P2166R1>`__","LWG","A Proposal to Prohibit std::basic_string and std::basic_string_view construction from nullptr","June 2021","|Complete|","13.0"
 "","","","","",""
-"`P0288R9 <https://wg21.link/P0288R9>`__","LWG","``any_invocable``","October 2021","",""
+"`P0288R9 <https://wg21.link/P0288R9>`__","LWG","``move_only_function``","October 2021","|Complete|","16.0"
 "`P0798R8 <https://wg21.link/P0798R8>`__","LWG","Monadic operations for ``std::optional``","October 2021","|Complete|","14.0"
 "`P0849R8 <https://wg21.link/P0849R8>`__","LWG","``auto(x)``: ``DECAY_COPY`` in the language","October 2021","|Complete|","14.0"
 "`P1072R10 <https://wg21.link/P1072R10>`__","LWG","``basic_string::resize_and_overwrite``","October 2021","|Complete|","14.0"

libcxx/include/CMakeLists.txt

@@ -315,6 +315,9 @@ set(files
   __functional/is_transparent.h
   __functional/mem_fn.h
   __functional/mem_fun_ref.h
+  __functional/move_only_function.h
+  __functional/move_only_function_common.h
+  __functional/move_only_function_impl.h
   __functional/not_fn.h
   __functional/operations.h
   __functional/perfect_forward.h

libcxx/include/__config

@@ -124,6 +124,8 @@
 // The implementation moved to the header, but we still export the symbols from
 // the dylib for backwards compatibility.
 #    define _LIBCPP_ABI_DO_NOT_EXPORT_TO_CHARS_BASE_10
+// Enable clang::trivial_abi for std::move_only_function
+#    define _LIBCPP_ABI_MOVE_ONLY_FUNCTION_TRIVIAL_ABI
 #  elif _LIBCPP_ABI_VERSION == 1
 #    if !(defined(_LIBCPP_OBJECT_FORMAT_COFF) || defined(_LIBCPP_OBJECT_FORMAT_XCOFF))
 // Enable compiling copies of now inline methods into the dylib to support

libcxx/include/__functional/move_only_function.h

@@ -0,0 +1,72 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_MOVE_ONLY_FUNCTION_H
+#define _LIBCPP___FUNCTIONAL_MOVE_ONLY_FUNCTION_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 20
+
+// NOLINTBEGIN(readability-duplicate-include)
+#  define _LIBCPP_IN_MOVE_ONLY_FUNCTION_H
+
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_REF &
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_REF &&
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_CV const
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_CV const
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_REF &
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_CV const
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_REF &&
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_NOEXCEPT true
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_NOEXCEPT true
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_REF &
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_NOEXCEPT true
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_REF &&
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_NOEXCEPT true
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_CV const
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_NOEXCEPT true
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_CV const
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_REF &
+#  include <__functional/move_only_function_impl.h>
+
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_NOEXCEPT true
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_CV const
+#  define _LIBCPP_MOVE_ONLY_FUNCTION_REF &&
+#  include <__functional/move_only_function_impl.h>
+
+#  undef _LIBCPP_IN_MOVE_ONLY_FUNCTION_H
+// NOLINTEND(readability-duplicate-include)
+
+#endif // _LIBCPP_STD_VER > 20
+
+#endif // _LIBCPP___FUNCTIONAL_MOVE_ONLY_FUNCTION_H

libcxx/include/__functional/move_only_function_common.h

@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_MOVE_ONLY_FUNCTION_COMMON_H
+#define _LIBCPP___FUNCTIONAL_MOVE_ONLY_FUNCTION_COMMON_H
+
+#include <__config>
+#include <__type_traits/integral_constant.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class...>
+class move_only_function;
+
+template <class...>
+struct __is_move_only_function : false_type {};
+
+template <class... _Args>
+struct __is_move_only_function<move_only_function<_Args...>> : true_type {};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_MOVE_ONLY_FUNCTION_COMMON_H