Move numerous components from <xstddef> to other headers and reduce inclusion

stl/inc/bit

@@ -12,6 +12,7 @@
 _EMIT_STL_WARNING(STL4038, "The contents of <bit> are available only with C++20 or later.");
 #else // ^^^ !_HAS_CXX20 / _HAS_CXX20 vvv
 
+#include <cstdlib>
 #include <isa_availability.h>
 #include <limits>
 #include <type_traits>

stl/inc/exception

@@ -9,6 +9,7 @@
 #include <yvals.h>
 #if _STL_COMPILER_PREPROCESSOR
 
+#include <cstdlib>
 #include <type_traits>
 
 #pragma pack(push, _CRT_PACKING)

stl/inc/functional

@@ -12,7 +12,6 @@
 #include <tuple>
 #include <typeinfo>
 #include <xmemory>
-#include <xstddef>
 #if _HAS_CXX17
 #ifdef _LEGACY_CODE_ASSUMES_FUNCTIONAL_INCLUDES_MEMORY
 #include <memory>
@@ -31,7 +30,7 @@ _STL_DISABLE_CLANG_WARNINGS
 #undef new
 
 _STD_BEGIN
-// plus, minus, and multiplies are defined in <xstddef>
+// plus, minus, and multiplies are defined in <xutility>
 
 _EXPORT_STD template <class _Ty = void>
 struct divides {
@@ -65,7 +64,8 @@ struct negate {
     }
 };
 
-// equal_to, not_equal_to, greater, less, greater_equal, and less_equal are defined in <xstddef>
+// less is defined in <type_traits>
+// equal_to, not_equal_to, greater, greater_equal, and less_equal are defined in <xutility>
 
 _EXPORT_STD template <class _Ty = void>
 struct logical_and {
@@ -142,7 +142,7 @@ struct bit_not {
     }
 };
 
-// void specializations of plus, minus, and multiplies are defined in <xstddef>
+// void specializations of plus, minus, and multiplies are defined in <xutility>
 
 template <>
 struct divides<void> {
@@ -175,8 +175,8 @@ struct negate<void> {
 
     using is_transparent = int;
 };
-
-// void specializations of equal_to, not_equal_to, greater, less, greater_equal, and less_equal are defined in <xstddef>
+// void specializations of less is defined in <type_traits>
+// void specializations of equal_to, not_equal_to, greater, greater_equal, and less_equal are defined in <xutility>
 
 template <>
 struct logical_and<void> {
@@ -302,6 +302,19 @@ _STL_RESTORE_DEPRECATED_WARNING
 
 #if _HAS_AUTO_PTR_ETC
 _STL_DISABLE_DEPRECATED_WARNING
+_EXPORT_STD template <class _Arg, class _Result>
+struct unary_function { // base class for unary functions
+    using argument_type = _Arg;
+    using result_type   = _Result;
+};
+
+_EXPORT_STD template <class _Arg1, class _Arg2, class _Result>
+struct binary_function { // base class for binary functions
+    using first_argument_type  = _Arg1;
+    using second_argument_type = _Arg2;
+    using result_type          = _Result;
+};
+
 _EXPORT_STD template <class _Fn>
 class binder1st : public unary_function<typename _Fn::second_argument_type,
                       typename _Fn::result_type> { // functor adapter _Func(stored, right)

stl/inc/iosfwd

@@ -12,7 +12,7 @@
 #include <cstdio>
 #include <cstring>
 #include <cwchar>
-#include <xstddef>
+#include <xtr1common>
 
 #pragma pack(push, _CRT_PACKING)
 #pragma warning(push, _STL_WARNING_LEVEL)

stl/inc/limits

@@ -12,7 +12,7 @@
 #include <climits>
 #include <cwchar>
 #include <isa_availability.h>
-#include <xstddef>
+#include <xtr1common>
 
 #include _STL_INTRIN_HEADER
 

stl/inc/type_traits

@@ -384,6 +384,133 @@ struct is_compound : bool_constant<!is_fundamental_v<_Ty>> {}; // determine whet
 _EXPORT_STD template <class _Ty>
 _INLINE_VAR constexpr bool is_compound_v = !is_fundamental_v<_Ty>;
 
+#define _EMIT_CDECL(FUNC, OPT1, OPT2, OPT3) FUNC(__cdecl, OPT1, OPT2, OPT3)
+
+#ifdef _M_CEE
+#define _EMIT_CLRCALL(FUNC, OPT1, OPT2, OPT3) FUNC(__clrcall, OPT1, OPT2, OPT3)
+
+#else // _M_CEE
+#define _EMIT_CLRCALL(FUNC, OPT1, OPT2, OPT3)
+#endif // _M_CEE
+
+#if defined(_M_IX86) && !defined(_M_CEE)
+#define _EMIT_FASTCALL(FUNC, OPT1, OPT2, OPT3) FUNC(__fastcall, OPT1, OPT2, OPT3)
+
+#else // defined(_M_IX86) && !defined(_M_CEE)
+#define _EMIT_FASTCALL(FUNC, OPT1, OPT2, OPT3)
+#endif // defined(_M_IX86) && !defined(_M_CEE)
+
+#ifdef _M_IX86
+#define _EMIT_STDCALL(FUNC, OPT1, OPT2, OPT3)  FUNC(__stdcall, OPT1, OPT2, OPT3)
+#define _EMIT_THISCALL(FUNC, OPT1, OPT2, OPT3) FUNC(__thiscall, OPT1, OPT2, OPT3)
+
+#else // _M_IX86
+#define _EMIT_STDCALL(FUNC, OPT1, OPT2, OPT3)
+#define _EMIT_THISCALL(FUNC, OPT1, OPT2, OPT3)
+#endif // _M_IX86
+
+#if ((defined(_M_IX86) && _M_IX86_FP >= 2) || defined(_M_X64)) && !defined(_M_CEE)
+#define _EMIT_VECTORCALL(FUNC, OPT1, OPT2, OPT3) FUNC(__vectorcall, OPT1, OPT2, OPT3)
+
+#else // defined(_M_IX86) && _M_IX86_FP >= 2 etc.
+#define _EMIT_VECTORCALL(FUNC, OPT1, OPT2, OPT3)
+#endif // defined(_M_IX86) && _M_IX86_FP >= 2 etc.
+
+#define _NON_MEMBER_CALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT) \
+    _EMIT_CDECL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)          \
+    _EMIT_CLRCALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)        \
+    _EMIT_FASTCALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)       \
+    _EMIT_STDCALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)        \
+    _EMIT_VECTORCALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)
+
+#define _NON_MEMBER_CALL_CV(FUNC, REF_OPT, NOEXCEPT_OPT)    \
+    _NON_MEMBER_CALL(FUNC, , REF_OPT, NOEXCEPT_OPT)         \
+    _NON_MEMBER_CALL(FUNC, const, REF_OPT, NOEXCEPT_OPT)    \
+    _NON_MEMBER_CALL(FUNC, volatile, REF_OPT, NOEXCEPT_OPT) \
+    _NON_MEMBER_CALL(FUNC, const volatile, REF_OPT, NOEXCEPT_OPT)
+
+#define _NON_MEMBER_CALL_CV_REF(FUNC, NOEXCEPT_OPT) \
+    _NON_MEMBER_CALL_CV(FUNC, , NOEXCEPT_OPT)       \
+    _NON_MEMBER_CALL_CV(FUNC, &, NOEXCEPT_OPT)      \
+    _NON_MEMBER_CALL_CV(FUNC, &&, NOEXCEPT_OPT)
+
+#ifdef __cpp_noexcept_function_type
+#define _NON_MEMBER_CALL_CV_REF_NOEXCEPT(FUNC) \
+    _NON_MEMBER_CALL_CV_REF(FUNC, )            \
+    _NON_MEMBER_CALL_CV_REF(FUNC, noexcept)
+#else // __cpp_noexcept_function_type
+#define _NON_MEMBER_CALL_CV_REF_NOEXCEPT(FUNC) _NON_MEMBER_CALL_CV_REF(FUNC, )
+#endif // __cpp_noexcept_function_type
+
+#define _MEMBER_CALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT) \
+    _EMIT_CDECL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)      \
+    _EMIT_CLRCALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)    \
+    _EMIT_FASTCALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)   \
+    _EMIT_STDCALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)    \
+    _EMIT_THISCALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)   \
+    _EMIT_VECTORCALL(FUNC, CV_OPT, REF_OPT, NOEXCEPT_OPT)
+
+#define _MEMBER_CALL_CV(FUNC, REF_OPT, NOEXCEPT_OPT)    \
+    _MEMBER_CALL(FUNC, , REF_OPT, NOEXCEPT_OPT)         \
+    _MEMBER_CALL(FUNC, const, REF_OPT, NOEXCEPT_OPT)    \
+    _MEMBER_CALL(FUNC, volatile, REF_OPT, NOEXCEPT_OPT) \
+    _MEMBER_CALL(FUNC, const volatile, REF_OPT, NOEXCEPT_OPT)
+
+#define _MEMBER_CALL_CV_REF(FUNC, NOEXCEPT_OPT) \
+    _MEMBER_CALL_CV(FUNC, , NOEXCEPT_OPT)       \
+    _MEMBER_CALL_CV(FUNC, &, NOEXCEPT_OPT)      \
+    _MEMBER_CALL_CV(FUNC, &&, NOEXCEPT_OPT)
+
+#ifdef __cpp_noexcept_function_type
+#define _MEMBER_CALL_CV_REF_NOEXCEPT(FUNC) \
+    _MEMBER_CALL_CV_REF(FUNC, )            \
+    _MEMBER_CALL_CV_REF(FUNC, noexcept)
+#else // __cpp_noexcept_function_type
+#define _MEMBER_CALL_CV_REF_NOEXCEPT(FUNC) _MEMBER_CALL_CV_REF(FUNC, )
+#endif // __cpp_noexcept_function_type
+
+#ifdef __cpp_noexcept_function_type
+#define _CLASS_DEFINE_CV_REF_NOEXCEPT(CLASS) \
+    CLASS(_EMPTY_ARGUMENT)                   \
+    CLASS(const)                             \
+    CLASS(volatile)                          \
+    CLASS(const volatile)                    \
+    CLASS(&)                                 \
+    CLASS(const&)                            \
+    CLASS(volatile&)                         \
+    CLASS(const volatile&)                   \
+    CLASS(&&)                                \
+    CLASS(const&&)                           \
+    CLASS(volatile&&)                        \
+    CLASS(const volatile&&)                  \
+    CLASS(noexcept)                          \
+    CLASS(const noexcept)                    \
+    CLASS(volatile noexcept)                 \
+    CLASS(const volatile noexcept)           \
+    CLASS(&noexcept)                         \
+    CLASS(const& noexcept)                   \
+    CLASS(volatile& noexcept)                \
+    CLASS(const volatile& noexcept)          \
+    CLASS(&&noexcept)                        \
+    CLASS(const&& noexcept)                  \
+    CLASS(volatile&& noexcept)               \
+    CLASS(const volatile&& noexcept)
+#else // __cpp_noexcept_function_type
+#define _CLASS_DEFINE_CV_REF_NOEXCEPT(CLASS) \
+    CLASS(_EMPTY_ARGUMENT)                   \
+    CLASS(const)                             \
+    CLASS(volatile)                          \
+    CLASS(const volatile)                    \
+    CLASS(&)                                 \
+    CLASS(const&)                            \
+    CLASS(volatile&)                         \
+    CLASS(const volatile&)                   \
+    CLASS(&&)                                \
+    CLASS(const&&)                           \
+    CLASS(volatile&&)                        \
+    CLASS(const volatile&&)
+#endif // __cpp_noexcept_function_type
+
 template <class... _Types>
 struct _Arg_types {}; // provide argument_type, etc. when sizeof...(_Types) is 1 or 2
 
@@ -1471,6 +1598,36 @@ _NODISCARD _MSVC_INTRINSIC constexpr //
     return _STD move(_Arg);
 }
 
+_EXPORT_STD template <class _Ty>
+_NODISCARD constexpr _Ty* addressof(_Ty& _Val) noexcept {
+    return __builtin_addressof(_Val);
+}
+
+_EXPORT_STD template <class _Ty>
+const _Ty* addressof(const _Ty&&) = delete;
+
+#pragma warning(push)
+#pragma warning(disable : 5215) // '%s' a function parameter with a volatile qualified type is deprecated in C++20
+#pragma warning(disable : 5216) // '%s' a volatile qualified return type is deprecated in C++20
+
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-volatile"
+#endif // __clang__
+
+template <class _Ty>
+_NODISCARD _Ty _Fake_copy_init(_Ty) noexcept;
+// _Fake_copy_init<T>(E):
+// (1) has type T [decay_t<decltype((E))> if T is deduced],
+// (2) is well-formed if and only if E is implicitly convertible to T and T is destructible, and
+// (3) is non-throwing if and only if both conversion from decltype((E)) to T and destruction of T are non-throwing.
+
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif // __clang__
+
+#pragma warning(pop)
+
 _EXPORT_STD template <class _Ty>
 class reference_wrapper;
 
@@ -2294,6 +2451,30 @@ template <class _Kty>
 struct _Is_nothrow_hashable<_Kty, void_t<decltype(hash<_Kty>{}(_STD declval<const _Kty&>()))>>
     : bool_constant<noexcept(hash<_Kty>{}(_STD declval<const _Kty&>()))> {};
 
+_EXPORT_STD template <class _Ty = void>
+struct less {
+    using _FIRST_ARGUMENT_TYPE_NAME _CXX17_DEPRECATE_ADAPTOR_TYPEDEFS  = _Ty;
+    using _SECOND_ARGUMENT_TYPE_NAME _CXX17_DEPRECATE_ADAPTOR_TYPEDEFS = _Ty;
+    using _RESULT_TYPE_NAME _CXX17_DEPRECATE_ADAPTOR_TYPEDEFS          = bool;
+
+    _NODISCARD constexpr bool operator()(const _Ty& _Left, const _Ty& _Right) const
+        noexcept(noexcept(_Fake_copy_init<bool>(_Left < _Right))) /* strengthened */ {
+        return _Left < _Right;
+    }
+};
+
+template <>
+struct less<void> {
+    template <class _Ty1, class _Ty2>
+    _NODISCARD constexpr auto operator()(_Ty1&& _Left, _Ty2&& _Right) const
+        noexcept(noexcept(static_cast<_Ty1&&>(_Left) < static_cast<_Ty2&&>(_Right))) // strengthened
+        -> decltype(static_cast<_Ty1&&>(_Left) < static_cast<_Ty2&&>(_Right)) {
+        return static_cast<_Ty1&&>(_Left) < static_cast<_Ty2&&>(_Right);
+    }
+
+    using is_transparent = int;
+};
+
 // vvvvvvvvvv DERIVED FROM corecrt_internal_fltintrn.h vvvvvvvvvv
 
 template <class _FloatingType>

stl/inc/utility

@@ -8,8 +8,8 @@
 #define _UTILITY_
 #include <yvals_core.h>
 #if _STL_COMPILER_PREPROCESSOR
+#include <initializer_list>
 #include <type_traits>
-#include <xstddef>
 
 #ifdef __cpp_lib_concepts
 #include <concepts>
@@ -19,6 +19,10 @@
 #include <compare>
 #endif // _HAS_CXX20
 
+#if _HAS_CXX23
+#include <cstdlib>
+#endif // _HAS_CXX23
+
 #pragma pack(push, _CRT_PACKING)
 #pragma warning(push, _STL_WARNING_LEVEL)
 #pragma warning(disable : _STL_DISABLED_WARNINGS)

stl/inc/xlocinfo

@@ -14,7 +14,6 @@
 #include <cstdio> // TRANSITION, VSO-661721
 #include <cstdlib>
 #include <cwchar>
-#include <xstddef>
 #include <xstring>
 
 #pragma pack(push, _CRT_PACKING)

stl/inc/xmemory

@@ -27,6 +27,16 @@ _STL_DISABLE_CLANG_WARNINGS
 #undef new
 
 _STD_BEGIN
+template <class _Ptrty>
+_NODISCARD constexpr auto _Unfancy(_Ptrty _Ptr) noexcept { // converts from a fancy pointer to a plain pointer
+    return _STD addressof(*_Ptr);
+}
+
+template <class _Ty>
+_NODISCARD constexpr _Ty* _Unfancy(_Ty* _Ptr) noexcept { // do nothing for plain pointers
+    return _Ptr;
+}
+
 template <class _Ty>
 struct _NODISCARD _Tidy_guard { // class with destructor that calls _Tidy
     _Ty* _Target;