[libc++] Add missing includes for __type_traits details

[ldionne]

Summary

By convention, <type_traits> should include everything under type_traits.
This was found because <cmath> was missing the declaration for promote.

[jloser]

Looks reasonable. Do you see any value in adding a test that verifies each top-level include actually includes all of the granularized headers? E.g. that <type_traits> does indeed include all of the header files in <__type_traits>? I idly wonder if we have similar problems for any of the other top-level includes that have been granularized such as the ones reported by the following:

find libcxx/include -type d -maxdepth 1 -name '__*'
libcxx/include/__iterator
libcxx/include/__memory
libcxx/include/__support
libcxx/include/__chrono
libcxx/include/__numeric
libcxx/include/__ranges
libcxx/include/__type_traits
libcxx/include/__variant
libcxx/include/__compare
libcxx/include/__concepts
libcxx/include/__filesystem
libcxx/include/__utility
libcxx/include/__charconv
libcxx/include/__tuple
libcxx/include/__format
libcxx/include/__algorithm
libcxx/include/__ios
libcxx/include/__functional
libcxx/include/__coroutine
libcxx/include/__thread
libcxx/include/__fwd
libcxx/include/__memory_resource
libcxx/include/__debug_utils
libcxx/include/__bit
libcxx/include/__string
libcxx/include/__random

We can probably safely not worry about __debug_utils since it's private.

[Mordante]

In D139164#3968888, @jloser wrote:

Looks reasonable. Do you see any value in adding a test that verifies each top-level include actually includes all of the granularized headers? E.g. that <type_traits> does indeed include all of the header files in <__type_traits>? I idly wonder if we have similar problems for any of the other top-level includes that have been granularized such as the ones reported by the following:

<snip>

I think that would be useful, I love to have tooling that catches errors. Looking at the list this seems like an easy error to make. I recognize one file...

Thanks for the cleanup, LGTM!

[ldionne]

I am actually going to drop this change -- as we've discussed in a couple of other places already, while this is what we wanted to do as a policy, this doesn't work in some cases, so I won't make a change to go in that direction.

libcxx/include/type_traits

 #include <__type_traits/aligned_union.h>
 #include <__type_traits/alignment_of.h>
 #include <__type_traits/apply_cv.h>
 #include <__type_traits/can_extract_key.h>
 #include <__type_traits/common_reference.h>
 #include <__type_traits/common_type.h>
 #include <__type_traits/conditional.h>
 #include <__type_traits/conjunction.h>
+#include <__type_traits/copy_cv.h>
+#include <__type_traits/copy_cvref.h>
 #include <__type_traits/decay.h>
 #include <__type_traits/dependent_type.h>
 #include <__type_traits/disjunction.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/extent.h>
 #include <__type_traits/has_unique_object_representation.h>
 #include <__type_traits/has_virtual_destructor.h>
 #include <__type_traits/integral_constant.h>
 #include <__type_traits/is_abstract.h>
 #include <__type_traits/is_aggregate.h>
+#include <__type_traits/is_allocator.h>
 #include <__type_traits/is_arithmetic.h>
 #include <__type_traits/is_array.h>
 #include <__type_traits/is_assignable.h>
 #include <__type_traits/is_base_of.h>
 #include <__type_traits/is_bounded_array.h>
 #include <__type_traits/is_callable.h>
 #include <__type_traits/is_char_like_type.h>
 #include <__type_traits/is_class.h>
 #include <__type_traits/is_compound.h>
 #include <__type_traits/is_const.h>
 #include <__type_traits/is_constant_evaluated.h>
 #include <__type_traits/is_constructible.h>
 #include <__type_traits/is_convertible.h>
 #include <__type_traits/is_copy_assignable.h>
 #include <__type_traits/is_copy_constructible.h>
+#include <__type_traits/is_core_convertible.h>
 #include <__type_traits/is_default_constructible.h>
 #include <__type_traits/is_destructible.h>
 #include <__type_traits/is_empty.h>
 #include <__type_traits/is_enum.h>
 #include <__type_traits/is_final.h>
 #include <__type_traits/is_floating_point.h>
 #include <__type_traits/is_function.h>
 #include <__type_traits/is_fundamental.h>

 #include <__type_traits/is_nothrow_destructible.h>
 #include <__type_traits/is_nothrow_move_assignable.h>
 #include <__type_traits/is_nothrow_move_constructible.h>
 #include <__type_traits/is_null_pointer.h>
 #include <__type_traits/is_object.h>
 #include <__type_traits/is_pod.h>
 #include <__type_traits/is_pointer.h>
 #include <__type_traits/is_polymorphic.h>
+#include <__type_traits/is_primary_template.h>
 #include <__type_traits/is_reference.h>
 #include <__type_traits/is_reference_wrapper.h>
 #include <__type_traits/is_referenceable.h>
 #include <__type_traits/is_same.h>
 #include <__type_traits/is_scalar.h>
 #include <__type_traits/is_scoped_enum.h>
 #include <__type_traits/is_signed.h>
+#include <__type_traits/is_signed_integer.h>
 #include <__type_traits/is_standard_layout.h>
 #include <__type_traits/is_swappable.h>
 #include <__type_traits/is_trivial.h>
 #include <__type_traits/is_trivially_assignable.h>
 #include <__type_traits/is_trivially_constructible.h>
 #include <__type_traits/is_trivially_copy_assignable.h>
 #include <__type_traits/is_trivially_copy_constructible.h>
 #include <__type_traits/is_trivially_copyable.h>
 #include <__type_traits/is_trivially_default_constructible.h>
 #include <__type_traits/is_trivially_destructible.h>
 #include <__type_traits/is_trivially_move_assignable.h>
 #include <__type_traits/is_trivially_move_constructible.h>
 #include <__type_traits/is_unbounded_array.h>
 #include <__type_traits/is_union.h>
 #include <__type_traits/is_unsigned.h>
+#include <__type_traits/is_unsigned_integer.h>
+#include <__type_traits/is_valid_expansion.h>
 #include <__type_traits/is_void.h>
 #include <__type_traits/is_volatile.h>
+#include <__type_traits/lazy.h>
+#include <__type_traits/make_32_64_or_128_bit.h>
 #include <__type_traits/make_const_lvalue_ref.h>
 #include <__type_traits/make_signed.h>
 #include <__type_traits/make_unsigned.h>
 #include <__type_traits/maybe_const.h>
+#include <__type_traits/nat.h>
 #include <__type_traits/negation.h>
+#include <__type_traits/noexcept_move_assign_container.h>
+#include <__type_traits/promote.h>
 #include <__type_traits/rank.h>
 #include <__type_traits/remove_all_extents.h>
 #include <__type_traits/remove_const.h>
 #include <__type_traits/remove_const_ref.h>
 #include <__type_traits/remove_cv.h>
+#include <__type_traits/remove_cvref.h>
 #include <__type_traits/remove_extent.h>
 #include <__type_traits/remove_pointer.h>
 #include <__type_traits/remove_reference.h>
 #include <__type_traits/remove_volatile.h>
 #include <__type_traits/result_of.h>
 #include <__type_traits/type_identity.h>
+#include <__type_traits/type_list.h>
 #include <__type_traits/underlying_type.h>
 #include <__type_traits/void_t.h>
 #include <__utility/declval.h>
 #include <cstddef>
 #include <cstdint>
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #endif // _LIBCPP_TYPE_TRAITS