[libc++] Updates C++2b to C++23.

During the ISO C++ Committee meeting plenary session the C++23 Standard
has been voted as technical complete.

This updates the reference to c++2b to c++23 and updates the __cplusplus
macro.

Note since we use clang-tidy 16 a small work-around is needed. Clang
knows -std=c++23 but clang-tidy not so for now force the lit compiler
flag to use -std=c++2b instead of -std=c++23.

Reviewed By: #libc, philnik, jloser, ldionne

Differential Revision: https://reviews.llvm.org/D150795

Author: mordante

libcxx/cmake/caches/Generic-cxx2b.cmake renamed to libcxx/cmake/caches/Generic-cxx23.cmake

@@ -1,2 +1,2 @@
-set(LIBCXX_TEST_PARAMS "std=c++2b" CACHE STRING "")
+set(LIBCXX_TEST_PARAMS "std=c++23" CACHE STRING "")
 set(LIBCXXABI_TEST_PARAMS "${LIBCXX_TEST_PARAMS}" CACHE STRING "")

libcxx/docs/FeatureTestMacroTable.rst

@@ -298,7 +298,7 @@ Status
     ------------------------------------------------- -----------------
     ``__cpp_lib_unwrap_ref``                          ``201811L``
     ------------------------------------------------- -----------------
-    **C++ 2b**
+    **C++ 23**
     -------------------------------------------------------------------
     ``__cpp_lib_adaptor_iterator_pair_constructor``   ``202106L``
     ------------------------------------------------- -----------------

libcxx/docs/ReleaseNotes.rst

@@ -70,7 +70,7 @@ Deprecations and Removals
   includes are removed based on the language version used. Incidental transitive
   inclusions of the following headers have been removed:
 
-  - C++2b: ``atomic``, ``bit``, ``cstdint``, ``cstdlib``, ``cstring``, ``initializer_list``, ``limits``, ``new``,
+  - C++23: ``atomic``, ``bit``, ``cstdint``, ``cstdlib``, ``cstring``, ``initializer_list``, ``limits``, ``new``,
            ``stdexcept``, ``system_error``, ``type_traits``, ``typeinfo``
 
 - ``<algorithm>`` no longer includes ``<chrono>`` in any C++ version (it was previously included in C++17 and earlier).

libcxx/docs/Status/Cxx2b.rst renamed to libcxx/docs/Status/Cxx23.rst

@@ -1,7 +1,7 @@
-.. _cxx2b-status:
+.. _cxx23-status:
 
 ================================
-libc++ C++2b Status
+libc++ C++23 Status
 ================================
 
 .. include:: ../Helpers/Styles.rst
@@ -14,6 +14,7 @@ Overview
 ================================
 
 In November 2020, the C++ standard committee adopted the first changes to the next version of the C++ standard, known here as "C++2b" (probably to be C++23).
+In February 2023, the C++ standard committee approved this draft, and sent it to ISO for approval as C++23.
 
 This page shows the status of libc++; the status of clang's support of the language features is `here <https://clang.llvm.org/cxx_status.html#cxx23>`__.
 
@@ -27,13 +28,13 @@ The groups that have contributed papers:
 
 .. note:: "Nothing to do" means that no library changes were needed to implement this change.
 
-.. _paper-status-cxx2b:
+.. _paper-status-cxx23:
 
 Paper Status
 ====================================
 
 .. csv-table::
-   :file: Cxx2bPapers.csv
+   :file: Cxx23Papers.csv
    :header-rows: 1
    :widths: auto
 
@@ -48,13 +49,13 @@ Paper Status
       The formatter for ``stacktrace`` is not implemented, since ``stacktrace`` is
       not implemented yet.
 
-.. _issues-status-cxx2b:
+.. _issues-status-cxx23:
 
 Library Working Group Issues Status
 ====================================
 
 .. csv-table::
-   :file: Cxx2bIssues.csv
+   :file: Cxx23Issues.csv
    :header-rows: 1
    :widths: auto
 

libcxx/docs/Status/Cxx2bIssues.csv renamed to libcxx/docs/Status/Cxx23Issues.csv

@@ -12,7 +12,7 @@ libc++ Zip Status (P2321R2)
 Overview
 ========
 
-This document contains the status of the C++2b zip implementation in libc++.
+This document contains the status of the C++23 zip implementation in libc++.
 It is used to track both the status of the sub-projects of the effort and who
 is assigned to these sub-projects. This avoids duplicating effort.
 

libcxx/docs/Status/Cxx2bPapers.csv renamed to libcxx/docs/Status/Cxx23Papers.csv

@@ -42,7 +42,7 @@ Getting Started with libc++
    Status/Cxx14
    Status/Cxx17
    Status/Cxx20
-   Status/Cxx2b
+   Status/Cxx23
    Status/Format
    Status/Parallelism
    Status/Ranges
@@ -145,7 +145,7 @@ C++ Dialect Support
 * :ref:`C++14 - Complete <cxx14-status>`
 * :ref:`C++17 - In Progress <cxx17-status>`
 * :ref:`C++20 - In Progress <cxx20-status>`
-* :ref:`C++2b - In Progress <cxx2b-status>`
+* :ref:`C++23 - In Progress <cxx23-status>`
 * :ref:`C++ Feature Test Macro Status <feature-status>`
 
 

libcxx/docs/Status/Zip.rst

@@ -61,9 +61,11 @@
 #      define _LIBCPP_STD_VER 17
 #    elif __cplusplus <= 202002L
 #      define _LIBCPP_STD_VER 20
+#    elif __cplusplus <= 202302L
+#      define _LIBCPP_STD_VER 23
 #    else
 // Expected release year of the next C++ standard
-#      define _LIBCPP_STD_VER 23
+#      define _LIBCPP_STD_VER 26
 #    endif
 #  endif // _LIBCPP_STD_VER
 // NOLINTEND(libcpp-cpp-version-check)

libcxx/docs/index.rst

@@ -294,13 +294,13 @@ namespace std::ranges {
   // [range.zip], zip view
   template<input_range... Views>
     requires (view<Views> && ...) && (sizeof...(Views) > 0)
-  class zip_view;        // C++2b
+  class zip_view;        // C++23
 
   template<class... Views>
-    inline constexpr bool enable_borrowed_range<zip_view<Views...>> =    // C++2b
+    inline constexpr bool enable_borrowed_range<zip_view<Views...>> =    // C++23
       (enable_borrowed_range<Views> && ...);
 
-  namespace views { inline constexpr unspecified zip = unspecified; }    // C++2b
+  namespace views { inline constexpr unspecified zip = unspecified; }    // C++23
 
   // [range.as.rvalue]
   template <view V>