[libc++] Fix LWG3437 "__cpp_lib_polymorphic_allocator is in the wrong header"

[• Quuxplusone]

Summary

https://cplusplus.github.io/LWG/issue3437

[Mordante]

LGTM, I assume the CI failure are just a flaky tests since I can't see how it's related. (Especially since the feature hasn't been implemented yet.)

libcxx/docs/Status/Cxx2bIssues.csv

 "`3419 <https://wg21.link/LWG3419>`__","[algorithms.requirements]/15 doesn't reserve as many rights as it intends to","November 2020","",""
 "`3420 <https://wg21.link/LWG3420>`__","cpp17-iterator should check that the type looks like an iterator first","November 2020","|Complete|","14.0","|ranges|"
 "`3421 <https://wg21.link/LWG3421>`__","Imperfect ADL emulation for boolean-testable","November 2020","","","|ranges|"
 "`3425 <https://wg21.link/LWG3425>`__","``condition_variable_any`` fails to constrain its Lock parameters","November 2020","",""
 "`3426 <https://wg21.link/LWG3426>`__","``operator<=>(const unique_ptr<T, D>&, nullptr_t)`` can't get no satisfaction","November 2020","","","|spaceship|"
 "`3427 <https://wg21.link/LWG3427>`__","``operator<=>(const shared_ptr<T>&, nullptr_t)`` definition ill-formed","November 2020","","","|spaceship|"
 "`3428 <https://wg21.link/LWG3428>`__","``single_view``'s in place constructor should be explicit","November 2020","","","|ranges|"
 "`3434 <https://wg21.link/LWG3434>`__","``ios_base`` never reclaims memory for iarray and parray","November 2020","",""
-"`3437 <https://wg21.link/LWG3437>`__","``__cpp_lib_polymorphic_allocator`` is in the wrong header","November 2020","",""
+"`3437 <https://wg21.link/LWG3437>`__","``__cpp_lib_polymorphic_allocator`` is in the wrong header","November 2020","|Complete|","14.0"
 "`3446 <https://wg21.link/LWG3446>`__","``indirectly_readable_traits`` ambiguity for types with both ``value_type`` and ``element_type``","November 2020","","","|ranges|"
 "`3448 <https://wg21.link/LWG3448>`__","``transform_view``'s ``sentinel<false>`` not comparable with ``iterator<true>``","November 2020","","","|ranges|"
 "`3449 <https://wg21.link/LWG3449>`__","``take_view`` and ``take_while_view``'s ``sentinel<false>`` not comparable with their ``const iterator``","November 2020","","","|ranges|"
 "`3453 <https://wg21.link/LWG3453>`__","Generic code cannot call ``ranges::advance(i, s)``","November 2020","","","|ranges|"
 "`3455 <https://wg21.link/LWG3455>`__","Incorrect Postconditions on ``unique_ptr`` move assignment","November 2020","|Nothing To Do|",""
 "`3460 <https://wg21.link/LWG3460>`__","Unimplementable ``noop_coroutine_handle`` guarantees","November 2020","|Complete|","14.0"
 "`3461 <https://wg21.link/LWG3461>`__","``convertible_to``'s description mishandles cv-qualified ``void``","November 2020","",""
 "`3465 <https://wg21.link/LWG3465>`__","``compare_partial_order_fallback`` requires ``F < E``","November 2020","","","|spaceship|"

libcxx/include/version

__cpp_lib_nonmember_container_access                    201411L <array> <deque> <forward_list>
                                                                 <iterator> <list> <map>
                                                                 <regex> <set> <string>
                                                                 <unordered_map> <unordered_set> <vector>
 __cpp_lib_not_fn                                        201603L <functional>
 __cpp_lib_null_iterators                                201304L <iterator>
 __cpp_lib_optional                                      201606L <optional>
 __cpp_lib_out_ptr                                       202106L <memory>
 __cpp_lib_parallel_algorithm                            201603L <algorithm> <numeric>
-__cpp_lib_polymorphic_allocator                         201902L <memory>
+__cpp_lib_polymorphic_allocator                         201902L <memory_resource>
 __cpp_lib_quoted_string_io                              201304L <iomanip>
 __cpp_lib_ranges                                        201811L <algorithm> <functional> <iterator>
                                                                 <memory> <ranges>
 __cpp_lib_ranges_starts_ends_with                       202106L <algorithm>
 __cpp_lib_ranges_zip                                    202110L <ranges> <tuple> <utility>
 __cpp_lib_raw_memory_algorithms                         201606L <memory>
 __cpp_lib_remove_cvref                                  201711L <type_traits>
 __cpp_lib_result_of_sfinae                              201210L <functional> <type_traits>

libcxx/test/std/language.support/support.limits/support.limits.general/memory.version.pass.cpp

/*  Constant                                      Value
     __cpp_lib_allocator_traits_is_always_equal    201411L [C++17]
     __cpp_lib_assume_aligned                      201811L [C++20]
     __cpp_lib_atomic_value_initialization         201911L [C++20]
     __cpp_lib_constexpr_dynamic_alloc             201907L [C++20]
     __cpp_lib_constexpr_memory                    201811L [C++20]
     __cpp_lib_enable_shared_from_this             201603L [C++17]
     __cpp_lib_make_unique                         201304L [C++14]
     __cpp_lib_out_ptr                             202106L [C++2b]
-    __cpp_lib_polymorphic_allocator               201902L [C++20]
     __cpp_lib_ranges                              201811L [C++20]
     __cpp_lib_raw_memory_algorithms               201606L [C++17]
     __cpp_lib_shared_ptr_arrays                   201611L [C++17]
     __cpp_lib_shared_ptr_weak_type                201606L [C++17]
     __cpp_lib_smart_ptr_for_overwrite             202002L [C++20]
     __cpp_lib_to_address                          201711L [C++20]
     __cpp_lib_transparent_operators               201210L [C++14]
                                                   201510L [C++17]

 # ifdef __cpp_lib_make_unique
 #   error "__cpp_lib_make_unique should not be defined before c++14"
 # endif
 
 # ifdef __cpp_lib_out_ptr
 #   error "__cpp_lib_out_ptr should not be defined before c++2b"
 # endif
 
-# ifdef __cpp_lib_polymorphic_allocator
-#   error "__cpp_lib_polymorphic_allocator should not be defined before c++20"
-# endif
-
 # ifdef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should not be defined before c++20"
 # endif
 
 # ifdef __cpp_lib_raw_memory_algorithms
 #   error "__cpp_lib_raw_memory_algorithms should not be defined before c++17"
 # endif
 

 # if __cpp_lib_make_unique != 201304L
 #   error "__cpp_lib_make_unique should have the value 201304L in c++14"
 # endif
 
 # ifdef __cpp_lib_out_ptr
 #   error "__cpp_lib_out_ptr should not be defined before c++2b"
 # endif
 
-# ifdef __cpp_lib_polymorphic_allocator
-#   error "__cpp_lib_polymorphic_allocator should not be defined before c++20"
-# endif
-
 # ifdef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should not be defined before c++20"
 # endif
 
 # ifdef __cpp_lib_raw_memory_algorithms
 #   error "__cpp_lib_raw_memory_algorithms should not be defined before c++17"
 # endif
 

 # if __cpp_lib_make_unique != 201304L
 #   error "__cpp_lib_make_unique should have the value 201304L in c++17"
 # endif
 
 # ifdef __cpp_lib_out_ptr
 #   error "__cpp_lib_out_ptr should not be defined before c++2b"
 # endif
 
-# ifdef __cpp_lib_polymorphic_allocator
-#   error "__cpp_lib_polymorphic_allocator should not be defined before c++20"
-# endif
-
 # ifdef __cpp_lib_ranges
 #   error "__cpp_lib_ranges should not be defined before c++20"
 # endif
 
 # ifndef __cpp_lib_raw_memory_algorithms
 #   error "__cpp_lib_raw_memory_algorithms should be defined in c++17"
 # endif
 # if __cpp_lib_raw_memory_algorithms != 201606L

 #   error "__cpp_lib_make_unique should have the value 201304L in c++20"
 # endif
 
 # ifdef __cpp_lib_out_ptr
 #   error "__cpp_lib_out_ptr should not be defined before c++2b"
 # endif
 
 # if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_polymorphic_allocator
-#     error "__cpp_lib_polymorphic_allocator should be defined in c++20"
-#   endif
-#   if __cpp_lib_polymorphic_allocator != 201902L
-#     error "__cpp_lib_polymorphic_allocator should have the value 201902L in c++20"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_polymorphic_allocator
-#     error "__cpp_lib_polymorphic_allocator should not be defined because it is unimplemented in libc++!"
-#   endif
-# endif
-
-# if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_ranges
 #     error "__cpp_lib_ranges should be defined in c++20"
 #   endif
 #   if __cpp_lib_ranges != 201811L
 #     error "__cpp_lib_ranges should have the value 201811L in c++20"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_ranges

 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_out_ptr
 #     error "__cpp_lib_out_ptr should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
 # if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_polymorphic_allocator
-#     error "__cpp_lib_polymorphic_allocator should be defined in c++2b"
-#   endif
-#   if __cpp_lib_polymorphic_allocator != 201902L
-#     error "__cpp_lib_polymorphic_allocator should have the value 201902L in c++2b"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_polymorphic_allocator
-#     error "__cpp_lib_polymorphic_allocator should not be defined because it is unimplemented in libc++!"
-#   endif
-# endif
-
-# if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_ranges
 #     error "__cpp_lib_ranges should be defined in c++2b"
 #   endif
 #   if __cpp_lib_ranges != 201811L
 #     error "__cpp_lib_ranges should have the value 201811L in c++2b"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_ranges

libcxx/utils/generate_feature_test_macro_components.py

feature_test_macros = [ add_version_header(x) for x in [
   }, {
     "name": "__cpp_lib_parallel_algorithm",
     "values": { "c++17": 201603 },
     "headers": ["algorithm", "numeric"],
     "unimplemented": True,
   }, {
     "name": "__cpp_lib_polymorphic_allocator",
     "values": { "c++20": 201902 },
-    "headers": ["memory"],
+    "headers": ["memory_resource"],
     "unimplemented": True,
   }, {
     "name": "__cpp_lib_quoted_string_io",
     "values": { "c++14": 201304 },
     "headers": ["iomanip"],
   }, {
     "name": "__cpp_lib_ranges",
     "values": { "c++20": 201811 },