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1// -*- C++ -*-2//===----------------------------------------------------------------------===//3//4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5// See https://llvm.org/LICENSE.txt for license information.6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP_VARIANT11#define _LIBCPP_VARIANT12 13/*14 variant synopsis15 16namespace std {17 18 // 20.7.2, class template variant19 template <class... Types>20 class variant {21 public:22 23 // 20.7.2.1, constructors24 constexpr variant() noexcept(see below);25 constexpr variant(const variant&);26 constexpr variant(variant&&) noexcept(see below);27 28 template <class T> constexpr variant(T&&) noexcept(see below);29 30 template <class T, class... Args>31 constexpr explicit variant(in_place_type_t<T>, Args&&...);32 33 template <class T, class U, class... Args>34 constexpr explicit variant(35 in_place_type_t<T>, initializer_list<U>, Args&&...);36 37 template <size_t I, class... Args>38 constexpr explicit variant(in_place_index_t<I>, Args&&...);39 40 template <size_t I, class U, class... Args>41 constexpr explicit variant(42 in_place_index_t<I>, initializer_list<U>, Args&&...);43 44 // 20.7.2.2, destructor45 constexpr ~variant(); // constexpr since c++2046 47 // 20.7.2.3, assignment48 constexpr variant& operator=(const variant&);49 constexpr variant& operator=(variant&&) noexcept(see below);50 51 template <class T>52 constexpr variant& operator=(T&&) noexcept(see below); // constexpr since c++2053 54 // 20.7.2.4, modifiers55 template <class T, class... Args>56 constexpr T& emplace(Args&&...); // constexpr since c++2057 58 template <class T, class U, class... Args>59 constexpr T& emplace(initializer_list<U>, Args&&...); // constexpr since c++2060 61 template <size_t I, class... Args>62 constexpr variant_alternative_t<I, variant>& emplace(Args&&...); // constexpr since c++2063 64 template <size_t I, class U, class... Args>65 constexpr variant_alternative_t<I, variant>&66 emplace(initializer_list<U>, Args&&...); // constexpr since c++2067 68 // 20.7.2.5, value status69 constexpr bool valueless_by_exception() const noexcept;70 constexpr size_t index() const noexcept;71 72 // 20.7.2.6, swap73 void swap(variant&) noexcept(see below);74 75 // [variant.visit], visitation76 template<class Self, class Visitor>77 constexpr decltype(auto) visit(this Self&&, Visitor&&); // Since C++2678 template<class R, class Self, class Visitor>79 constexpr R visit(this Self&&, Visitor&&); // Since C++2680 };81 82 // 20.7.3, variant helper classes83 template <class T> struct variant_size; // undefined84 85 template <class T>86 inline constexpr size_t variant_size_v = variant_size<T>::value;87 88 template <class T> struct variant_size<const T>;89 template <class T> struct variant_size<volatile T>;90 template <class T> struct variant_size<const volatile T>;91 92 template <class... Types>93 struct variant_size<variant<Types...>>;94 95 template <size_t I, class T> struct variant_alternative; // undefined96 97 template <size_t I, class T>98 using variant_alternative_t = typename variant_alternative<I, T>::type;99 100 template <size_t I, class T> struct variant_alternative<I, const T>;101 template <size_t I, class T> struct variant_alternative<I, volatile T>;102 template <size_t I, class T> struct variant_alternative<I, const volatile T>;103 104 template <size_t I, class... Types>105 struct variant_alternative<I, variant<Types...>>;106 107 inline constexpr size_t variant_npos = -1;108 109 // 20.7.4, value access110 template <class T, class... Types>111 constexpr bool holds_alternative(const variant<Types...>&) noexcept;112 113 template <size_t I, class... Types>114 constexpr variant_alternative_t<I, variant<Types...>>&115 get(variant<Types...>&);116 117 template <size_t I, class... Types>118 constexpr variant_alternative_t<I, variant<Types...>>&&119 get(variant<Types...>&&);120 121 template <size_t I, class... Types>122 constexpr variant_alternative_t<I, variant<Types...>> const&123 get(const variant<Types...>&);124 125 template <size_t I, class... Types>126 constexpr variant_alternative_t<I, variant<Types...>> const&&127 get(const variant<Types...>&&);128 129 template <class T, class... Types>130 constexpr T& get(variant<Types...>&);131 132 template <class T, class... Types>133 constexpr T&& get(variant<Types...>&&);134 135 template <class T, class... Types>136 constexpr const T& get(const variant<Types...>&);137 138 template <class T, class... Types>139 constexpr const T&& get(const variant<Types...>&&);140 141 template <size_t I, class... Types>142 constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>>143 get_if(variant<Types...>*) noexcept;144 145 template <size_t I, class... Types>146 constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>>147 get_if(const variant<Types...>*) noexcept;148 149 template <class T, class... Types>150 constexpr add_pointer_t<T>151 get_if(variant<Types...>*) noexcept;152 153 template <class T, class... Types>154 constexpr add_pointer_t<const T>155 get_if(const variant<Types...>*) noexcept;156 157 // 20.7.5, relational operators158 template <class... Types>159 constexpr bool operator==(const variant<Types...>&, const variant<Types...>&);160 161 template <class... Types>162 constexpr bool operator!=(const variant<Types...>&, const variant<Types...>&);163 164 template <class... Types>165 constexpr bool operator<(const variant<Types...>&, const variant<Types...>&);166 167 template <class... Types>168 constexpr bool operator>(const variant<Types...>&, const variant<Types...>&);169 170 template <class... Types>171 constexpr bool operator<=(const variant<Types...>&, const variant<Types...>&);172 173 template <class... Types>174 constexpr bool operator>=(const variant<Types...>&, const variant<Types...>&);175 176 template <class... Types> requires (three_way_comparable<Types> && ...)177 constexpr common_comparison_category_t<compare_three_way_result_t<Types>...>178 operator<=>(const variant<Types...>&, const variant<Types...>&); // since C++20179 180 // 20.7.6, visitation181 template <class Visitor, class... Variants>182 constexpr see below visit(Visitor&&, Variants&&...);183 184 template <class R, class Visitor, class... Variants>185 constexpr R visit(Visitor&&, Variants&&...); // since C++20186 187 // 20.7.7, class monostate188 struct monostate;189 190 // 20.7.8, monostate relational operators191 constexpr bool operator==(monostate, monostate) noexcept;192 constexpr bool operator!=(monostate, monostate) noexcept; // until C++20193 constexpr bool operator<(monostate, monostate) noexcept; // until C++20194 constexpr bool operator>(monostate, monostate) noexcept; // until C++20195 constexpr bool operator<=(monostate, monostate) noexcept; // until C++20196 constexpr bool operator>=(monostate, monostate) noexcept; // until C++20197 constexpr strong_ordering operator<=>(monostate, monostate) noexcept; // since C++20198 199 // 20.7.9, specialized algorithms200 template <class... Types>201 void swap(variant<Types...>&, variant<Types...>&) noexcept(see below);202 203 // 20.7.10, class bad_variant_access204 class bad_variant_access;205 206 // 20.7.11, hash support207 template <class T> struct hash;208 template <class... Types> struct hash<variant<Types...>>;209 template <> struct hash<monostate>;210 211} // namespace std212 213*/214 215#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)216# include <__cxx03/__config>217#else218# include <__compare/common_comparison_category.h>219# include <__compare/compare_three_way_result.h>220# include <__compare/ordering.h>221# include <__compare/three_way_comparable.h>222# include <__config>223# include <__exception/exception.h>224# include <__functional/hash.h>225# include <__functional/operations.h>226# include <__functional/unary_function.h>227# include <__fwd/variant.h>228# include <__memory/addressof.h>229# include <__memory/construct_at.h>230# include <__tuple/find_index.h>231# include <__tuple/sfinae_helpers.h>232# include <__type_traits/add_cv_quals.h>233# include <__type_traits/add_pointer.h>234# include <__type_traits/common_type.h>235# include <__type_traits/conditional.h>236# include <__type_traits/conjunction.h>237# include <__type_traits/decay.h>238# include <__type_traits/dependent_type.h>239# include <__type_traits/enable_if.h>240# include <__type_traits/invoke.h>241# include <__type_traits/is_array.h>242# include <__type_traits/is_assignable.h>243# include <__type_traits/is_constructible.h>244# include <__type_traits/is_convertible.h>245# include <__type_traits/is_core_convertible.h>246# include <__type_traits/is_destructible.h>247# include <__type_traits/is_nothrow_assignable.h>248# include <__type_traits/is_nothrow_constructible.h>249# include <__type_traits/is_reference.h>250# include <__type_traits/is_same.h>251# include <__type_traits/is_swappable.h>252# include <__type_traits/is_trivially_assignable.h>253# include <__type_traits/is_trivially_constructible.h>254# include <__type_traits/is_trivially_destructible.h>255# include <__type_traits/is_trivially_relocatable.h>256# include <__type_traits/is_void.h>257# include <__type_traits/remove_const.h>258# include <__type_traits/remove_cvref.h>259# include <__type_traits/remove_reference.h>260# include <__type_traits/type_identity.h>261# include <__type_traits/void_t.h>262# include <__utility/declval.h>263# include <__utility/forward.h>264# include <__utility/forward_like.h>265# include <__utility/in_place.h>266# include <__utility/integer_sequence.h>267# include <__utility/move.h>268# include <__utility/swap.h>269# include <__variant/monostate.h>270# include <__verbose_abort>271# include <initializer_list>272# include <limits>273# include <version>274 275// standard-mandated includes276 277// [variant.syn]278# include <compare>279 280# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)281# pragma GCC system_header282# endif283 284_LIBCPP_PUSH_MACROS285# include <__undef_macros>286 287_LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD288 289class _LIBCPP_EXPORTED_FROM_ABI bad_variant_access : public exception {290public:291 const char* what() const _NOEXCEPT override;292};293 294_LIBCPP_END_UNVERSIONED_NAMESPACE_STD295 296_LIBCPP_BEGIN_NAMESPACE_STD297 298# if _LIBCPP_STD_VER >= 17299 300// Light N-dimensional array of function pointers. Used in place of std::array to avoid301// adding a dependency.302template <class _Tp, size_t _Size>303struct __farray {304 static_assert(_Size > 0, "N-dimensional array should never be empty in std::visit");305 _Tp __buf_[_Size] = {};306 307 _LIBCPP_HIDE_FROM_ABI constexpr const _Tp& operator[](size_t __n) const noexcept { return __buf_[__n]; }308};309 310[[noreturn]] inline _LIBCPP_HIDE_FROM_ABI void __throw_bad_variant_access() {311# if _LIBCPP_HAS_EXCEPTIONS312 throw bad_variant_access();313# else314 _LIBCPP_VERBOSE_ABORT("bad_variant_access was thrown in -fno-exceptions mode");315# endif316}317 318// variant_size319template <class _Tp>320struct variant_size<const _Tp> : variant_size<_Tp> {};321 322template <class _Tp>323struct variant_size<volatile _Tp> : variant_size<_Tp> {};324 325template <class _Tp>326struct variant_size<const volatile _Tp> : variant_size<_Tp> {};327 328template <class... _Types>329struct variant_size<variant<_Types...>> : integral_constant<size_t, sizeof...(_Types)> {};330 331// variant_alternative332template <size_t _Ip, class _Tp>333struct variant_alternative<_Ip, const _Tp> : add_const<variant_alternative_t<_Ip, _Tp>> {};334 335template <size_t _Ip, class _Tp>336struct variant_alternative<_Ip, volatile _Tp> : add_volatile<variant_alternative_t<_Ip, _Tp>> {};337 338template <size_t _Ip, class _Tp>339struct variant_alternative<_Ip, const volatile _Tp> : add_cv<variant_alternative_t<_Ip, _Tp>> {};340 341template <size_t _Ip, class... _Types>342struct variant_alternative<_Ip, variant<_Types...>> {343 static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>");344 using type _LIBCPP_NODEBUG = __type_pack_element<_Ip, _Types...>;345};346 347template <size_t _NumAlternatives>348_LIBCPP_HIDE_FROM_ABI constexpr auto __choose_index_type() {349# ifdef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION350 if constexpr (_NumAlternatives < numeric_limits<unsigned char>::max())351 return static_cast<unsigned char>(0);352 else if constexpr (_NumAlternatives < numeric_limits<unsigned short>::max())353 return static_cast<unsigned short>(0);354 else355# endif // _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION356 return static_cast<unsigned int>(0);357}358 359template <size_t _NumAlts>360using __variant_index_t _LIBCPP_NODEBUG = decltype(std::__choose_index_type<_NumAlts>());361 362template <class _IndexType>363constexpr _IndexType __variant_npos = static_cast<_IndexType>(-1);364 365template <class... _Types>366_LIBCPP_HIDE_FROM_ABI constexpr variant<_Types...>& __as_variant(variant<_Types...>& __vs) noexcept {367 return __vs;368}369 370template <class... _Types>371_LIBCPP_HIDE_FROM_ABI constexpr const variant<_Types...>& __as_variant(const variant<_Types...>& __vs) noexcept {372 return __vs;373}374 375template <class... _Types>376_LIBCPP_HIDE_FROM_ABI constexpr variant<_Types...>&& __as_variant(variant<_Types...>&& __vs) noexcept {377 return std::move(__vs);378}379 380template <class... _Types>381_LIBCPP_HIDE_FROM_ABI constexpr const variant<_Types...>&& __as_variant(const variant<_Types...>&& __vs) noexcept {382 return std::move(__vs);383}384 385namespace __find_detail {386 387template <class _Tp, class... _Types>388_LIBCPP_HIDE_FROM_ABI constexpr size_t __find_index() {389 constexpr bool __matches[] = {is_same_v<_Tp, _Types>...};390 size_t __result = __not_found;391 for (size_t __i = 0; __i < sizeof...(_Types); ++__i) {392 if (__matches[__i]) {393 if (__result != __not_found) {394 return __ambiguous;395 }396 __result = __i;397 }398 }399 return __result;400}401 402template <size_t _Index>403struct __find_unambiguous_index_sfinae_impl : integral_constant<size_t, _Index> {};404 405template <>406struct __find_unambiguous_index_sfinae_impl<__not_found> {};407 408template <>409struct __find_unambiguous_index_sfinae_impl<__ambiguous> {};410 411template <class _Tp, class... _Types>412struct __find_unambiguous_index_sfinae413 : __find_unambiguous_index_sfinae_impl<__find_detail::__find_index<_Tp, _Types...>()> {};414 415} // namespace __find_detail416 417namespace __variant_detail {418 419struct __valueless_t {};420 421enum class _Trait { _TriviallyAvailable, _Available, _Unavailable };422 423template <typename _Tp, template <typename> class _IsTriviallyAvailable, template <typename> class _IsAvailable>424constexpr _Trait __trait =425 _IsTriviallyAvailable<_Tp>::value ? _Trait::_TriviallyAvailable426 : _IsAvailable<_Tp>::value427 ? _Trait::_Available428 : _Trait::_Unavailable;429 430_LIBCPP_HIDE_FROM_ABI constexpr _Trait __common_trait(initializer_list<_Trait> __traits) {431 _Trait __result = _Trait::_TriviallyAvailable;432 for (_Trait __t : __traits) {433 if (static_cast<int>(__t) > static_cast<int>(__result)) {434 __result = __t;435 }436 }437 return __result;438}439 440template <typename... _Types>441struct __traits {442 static constexpr _Trait __copy_constructible_trait =443 __variant_detail::__common_trait({__trait<_Types, is_trivially_copy_constructible, is_copy_constructible>...});444 445 static constexpr _Trait __move_constructible_trait =446 __variant_detail::__common_trait({__trait<_Types, is_trivially_move_constructible, is_move_constructible>...});447 448 static constexpr _Trait __copy_assignable_trait = __variant_detail::__common_trait(449 {__copy_constructible_trait, __trait<_Types, is_trivially_copy_assignable, is_copy_assignable>...});450 451 static constexpr _Trait __move_assignable_trait = __variant_detail::__common_trait(452 {__move_constructible_trait, __trait<_Types, is_trivially_move_assignable, is_move_assignable>...});453 454 static constexpr _Trait __destructible_trait =455 __variant_detail::__common_trait({__trait<_Types, is_trivially_destructible, is_destructible>...});456};457 458namespace __access {459 460struct __union {461 template <class _Vp>462 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<0>) {463 return std::forward<_Vp>(__v).__head;464 }465 466 template <class _Vp, size_t _Ip>467 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<_Ip>) {468 return __get_alt(std::forward<_Vp>(__v).__tail, in_place_index<_Ip - 1>);469 }470};471 472struct __base {473 template <size_t _Ip, class _Vp>474 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v) {475 return __union::__get_alt(std::forward<_Vp>(__v).__data, in_place_index<_Ip>);476 }477};478 479struct __variant {480 template <size_t _Ip, class _Vp>481 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v) {482 return __base::__get_alt<_Ip>(std::forward<_Vp>(__v).__impl_);483 }484};485 486} // namespace __access487 488namespace __visitation {489 490struct __base {491 template <class _Visitor, class... _Vs>492 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)493 __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {494 constexpr auto __fdiagonal = __make_fdiagonal<_Visitor&&, decltype(std::forward<_Vs>(__vs).__as_base())...>();495 return __fdiagonal[__index](std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__as_base()...);496 }497 498 template <class _Visitor, class... _Vs>499 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) {500 constexpr auto __fmatrix = __make_fmatrix<_Visitor&&, decltype(std::forward<_Vs>(__vs).__as_base())...>();501 return __at(__fmatrix, __vs.index()...)(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__as_base()...);502 }503 504private:505 template <class _Tp>506 _LIBCPP_HIDE_FROM_ABI static constexpr const _Tp& __at(const _Tp& __elem) {507 return __elem;508 }509 510 template <class _Tp, size_t _Np, typename... _Indices>511 _LIBCPP_HIDE_FROM_ABI static constexpr auto&&512 __at(const __farray<_Tp, _Np>& __elems, size_t __index, _Indices... __indices) {513 return __at(__elems[__index], __indices...);514 }515 516 template <class _Fp, class... _Fs>517 static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_visitor_return_type_check() {518 static_assert(519 __all<is_same_v<_Fp, _Fs>...>::value, "`std::visit` requires the visitor to have a single return type.");520 }521 522 template <class... _Fs>523 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_farray(_Fs&&... __fs) {524 __std_visit_visitor_return_type_check<__remove_cvref_t<_Fs>...>();525 using __result = __farray<common_type_t<__remove_cvref_t<_Fs>...>, sizeof...(_Fs)>;526 return __result{{std::forward<_Fs>(__fs)...}};527 }528 529 template <size_t... _Is>530 struct __dispatcher {531 template <class _Fp, class... _Vs>532 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) {533 return std::__invoke(static_cast<_Fp>(__f), __access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...);534 }535 };536 537 template <class _Fp, class... _Vs, size_t... _Is>538 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_dispatch(index_sequence<_Is...>) {539 return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>;540 }541 542 template <size_t _Ip, class _Fp, class... _Vs>543 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal_impl() {544 return __make_dispatch<_Fp, _Vs...>(index_sequence<((void)__type_identity<_Vs>{}, _Ip)...>{});545 }546 547 template <class _Fp, class... _Vs, size_t... _Is>548 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) {549 return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...);550 }551 552 template <class _Fp, class _Vp, class... _Vs>553 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal() {554 constexpr size_t __np = __remove_cvref_t<_Vp>::__size();555 static_assert(__all<(__np == __remove_cvref_t<_Vs>::__size())...>::value);556 return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<__np>{});557 }558 559 template <class _Fp, class... _Vs, size_t... _Is>560 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) {561 return __make_dispatch<_Fp, _Vs...>(__is);562 }563 564 template <class _Fp, class... _Vs, size_t... _Is, size_t... _Js, class... _Ls>565 _LIBCPP_HIDE_FROM_ABI static constexpr auto566 __make_fmatrix_impl(index_sequence<_Is...>, index_sequence<_Js...>, _Ls... __ls) {567 return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>(index_sequence<_Is..., _Js>{}, __ls...)...);568 }569 570 template <class _Fp, class... _Vs>571 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fmatrix() {572 return __make_fmatrix_impl<_Fp, _Vs...>(573 index_sequence<>{}, make_index_sequence<__remove_cvref_t<_Vs>::__size()>{}...);574 }575};576 577struct __variant {578 template <class _Visitor, class... _Vs>579 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)580 __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {581 return __base::__visit_alt_at(__index, std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__impl_...);582 }583 584 template <class _Visitor, class... _Vs>585 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) {586 return __base::__visit_alt(587 std::forward<_Visitor>(__visitor), std::__as_variant(std::forward<_Vs>(__vs)).__impl_...);588 }589 590 template <class _Visitor, class... _Vs>591 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)592 __visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {593 return __visit_alt_at(__index, __make_value_visitor(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...);594 }595 596 template <class _Visitor, class... _Vs>597 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_value(_Visitor&& __visitor, _Vs&&... __vs) {598 return __visit_alt(__make_value_visitor(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...);599 }600 601# if _LIBCPP_STD_VER >= 20602 template <class _Rp, class _Visitor, class... _Vs>603 _LIBCPP_HIDE_FROM_ABI static constexpr _Rp __visit_value(_Visitor&& __visitor, _Vs&&... __vs) {604 return __visit_alt(__make_value_visitor<_Rp>(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...);605 }606# endif607 608private:609 template <class _Visitor, class... _Values>610 static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_exhaustive_visitor_check() {611 static_assert(is_invocable_v<_Visitor, _Values...>, "`std::visit` requires the visitor to be exhaustive.");612 }613 614 template <class _Visitor>615 struct __value_visitor {616 template <class... _Alts>617 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Alts&&... __alts) const {618 __std_visit_exhaustive_visitor_check< _Visitor, decltype((std::forward<_Alts>(__alts).__value))...>();619 return std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...);620 }621 _Visitor&& __visitor;622 };623 624# if _LIBCPP_STD_VER >= 20625 template <class _Rp, class _Visitor>626 struct __value_visitor_return_type {627 template <class... _Alts>628 _LIBCPP_HIDE_FROM_ABI constexpr _Rp operator()(_Alts&&... __alts) const {629 __std_visit_exhaustive_visitor_check< _Visitor, decltype((std::forward<_Alts>(__alts).__value))...>();630 if constexpr (is_void_v<_Rp>) {631 std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...);632 } else {633 return std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...);634 }635 }636 637 _Visitor&& __visitor;638 };639# endif640 641 template <class _Visitor>642 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_value_visitor(_Visitor&& __visitor) {643 return __value_visitor<_Visitor>{std::forward<_Visitor>(__visitor)};644 }645 646# if _LIBCPP_STD_VER >= 20647 template <class _Rp, class _Visitor>648 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_value_visitor(_Visitor&& __visitor) {649 return __value_visitor_return_type<_Rp, _Visitor>{std::forward<_Visitor>(__visitor)};650 }651# endif652};653 654} // namespace __visitation655 656// Adding semi-colons in macro expansions helps clang-format to do a better job.657// This macro is used to avoid compilation errors due to "stray" semi-colons.658# define _LIBCPP_EAT_SEMICOLON static_assert(true, "")659 660template <size_t _Index, class _Tp>661struct __alt {662 using __value_type _LIBCPP_NODEBUG = _Tp;663 static constexpr size_t __index = _Index;664 665 template <class... _Args>666 _LIBCPP_HIDE_FROM_ABI explicit constexpr __alt(in_place_t, _Args&&... __args)667 : __value(std::forward<_Args>(__args)...) {}668 669 __value_type __value;670};671 672template <_Trait _DestructibleTrait, size_t _Index, class... _Types>673union __union;674 675template <_Trait _DestructibleTrait, size_t _Index>676union __union<_DestructibleTrait, _Index> {};677 678# define _LIBCPP_VARIANT_UNION(destructible_trait, destructor_definition) \679 template <size_t _Index, class _Tp, class... _Types> \680 union __union<destructible_trait, _Index, _Tp, _Types...> { \681 public: \682 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(__valueless_t) noexcept : __dummy{} {} \683 \684 template <class... _Args> \685 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(in_place_index_t<0>, _Args&&... __args) \686 : __head(in_place, std::forward<_Args>(__args)...) {} \687 \688 template <size_t _Ip, class... _Args> \689 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(in_place_index_t<_Ip>, _Args&&... __args) \690 : __tail(in_place_index<_Ip - 1>, std::forward<_Args>(__args)...) {} \691 \692 _LIBCPP_HIDE_FROM_ABI __union(const __union&) = default; \693 _LIBCPP_HIDE_FROM_ABI __union(__union&&) = default; \694 _LIBCPP_HIDE_FROM_ABI __union& operator=(const __union&) = default; \695 _LIBCPP_HIDE_FROM_ABI __union& operator=(__union&&) = default; \696 destructor_definition; \697 \698 private: \699 char __dummy; \700 __alt<_Index, _Tp> __head; \701 __union<destructible_trait, _Index + 1, _Types...> __tail; \702 \703 friend struct __access::__union; \704 }705 706_LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable,707 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = default);708_LIBCPP_VARIANT_UNION(709 _Trait::_Available, _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() {} _LIBCPP_EAT_SEMICOLON);710_LIBCPP_VARIANT_UNION(_Trait::_Unavailable, _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = delete);711 712# undef _LIBCPP_VARIANT_UNION713 714template <_Trait _DestructibleTrait, class... _Types>715class __base {716public:717 using __index_t _LIBCPP_NODEBUG = __variant_index_t<sizeof...(_Types)>;718 719 _LIBCPP_HIDE_FROM_ABI explicit constexpr __base(__valueless_t __tag) noexcept720 : __data(__tag), __index(__variant_npos<__index_t>) {}721 722 template <size_t _Ip, class... _Args>723 _LIBCPP_HIDE_FROM_ABI explicit constexpr __base(in_place_index_t<_Ip>, _Args&&... __args)724 : __data(in_place_index<_Ip>, std::forward<_Args>(__args)...), __index(_Ip) {}725 726 _LIBCPP_HIDE_FROM_ABI constexpr bool valueless_by_exception() const noexcept { return index() == variant_npos; }727 728 _LIBCPP_HIDE_FROM_ABI constexpr size_t index() const noexcept {729 return __index == __variant_npos<__index_t> ? variant_npos : __index;730 }731 732protected:733 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() & { return *this; }734 735 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() && { return std::move(*this); }736 737 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() const& { return *this; }738 739 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() const&& { return std::move(*this); }740 741 _LIBCPP_HIDE_FROM_ABI static constexpr size_t __size() { return sizeof...(_Types); }742 743 __union<_DestructibleTrait, 0, _Types...> __data;744 __index_t __index;745 746 friend struct __access::__base;747 friend struct __visitation::__base;748};749 750template <class _Traits, _Trait = _Traits::__destructible_trait>751class __dtor;752 753# define _LIBCPP_VARIANT_DESTRUCTOR(destructible_trait, destructor_definition, destroy) \754 template <class... _Types> \755 class __dtor<__traits<_Types...>, destructible_trait> : public __base<destructible_trait, _Types...> { \756 using __base_type _LIBCPP_NODEBUG = __base<destructible_trait, _Types...>; \757 using __index_t _LIBCPP_NODEBUG = typename __base_type::__index_t; \758 \759 public: \760 using __base_type::__base_type; \761 using __base_type::operator=; \762 _LIBCPP_HIDE_FROM_ABI __dtor(const __dtor&) = default; \763 _LIBCPP_HIDE_FROM_ABI __dtor(__dtor&&) = default; \764 _LIBCPP_HIDE_FROM_ABI __dtor& operator=(const __dtor&) = default; \765 _LIBCPP_HIDE_FROM_ABI __dtor& operator=(__dtor&&) = default; \766 destructor_definition; \767 \768 protected: \769 destroy; \770 }771 772_LIBCPP_VARIANT_DESTRUCTOR(773 _Trait::_TriviallyAvailable,774 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = default,775 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept {776 this->__index = __variant_npos<__index_t>;777 } _LIBCPP_EAT_SEMICOLON);778 779_LIBCPP_VARIANT_DESTRUCTOR(780 _Trait::_Available,781 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() { __destroy(); } _LIBCPP_EAT_SEMICOLON,782 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept {783 if (!this->valueless_by_exception()) {784 __visitation::__base::__visit_alt(785 [](auto& __alt) noexcept {786 using __alt_type = __remove_cvref_t<decltype(__alt)>;787 __alt.~__alt_type();788 },789 *this);790 }791 this->__index = __variant_npos<__index_t>;792 } _LIBCPP_EAT_SEMICOLON);793 794_LIBCPP_VARIANT_DESTRUCTOR(_Trait::_Unavailable,795 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = delete,796 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept = delete);797 798# undef _LIBCPP_VARIANT_DESTRUCTOR799 800template <class _Traits>801class __ctor : public __dtor<_Traits> {802 using __base_type _LIBCPP_NODEBUG = __dtor<_Traits>;803 804public:805 using __base_type::__base_type;806 using __base_type::operator=;807 808protected:809 template <class _Rhs>810 _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_construct(__ctor& __lhs, _Rhs&& __rhs) {811 __lhs.__destroy();812 if (!__rhs.valueless_by_exception()) {813 auto __rhs_index = __rhs.index();814 __visitation::__base::__visit_alt_at(815 __rhs_index,816 [&__lhs](auto&& __rhs_alt) {817 std::__construct_at(std::addressof(__lhs.__data),818 in_place_index<__decay_t<decltype(__rhs_alt)>::__index>,819 std::forward<decltype(__rhs_alt)>(__rhs_alt).__value);820 },821 std::forward<_Rhs>(__rhs));822 __lhs.__index = __rhs_index;823 }824 }825};826 827template <class _Traits, _Trait = _Traits::__move_constructible_trait>828class __move_constructor;829 830# define _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait, move_constructor_definition) \831 template <class... _Types> \832 class __move_constructor<__traits<_Types...>, move_constructible_trait> : public __ctor<__traits<_Types...>> { \833 using __base_type _LIBCPP_NODEBUG = __ctor<__traits<_Types...>>; \834 \835 public: \836 using __base_type::__base_type; \837 using __base_type::operator=; \838 \839 _LIBCPP_HIDE_FROM_ABI __move_constructor(const __move_constructor&) = default; \840 _LIBCPP_HIDE_FROM_ABI ~__move_constructor() = default; \841 _LIBCPP_HIDE_FROM_ABI __move_constructor& operator=(const __move_constructor&) = default; \842 _LIBCPP_HIDE_FROM_ABI __move_constructor& operator=(__move_constructor&&) = default; \843 move_constructor_definition; \844 }845 846_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(847 _Trait::_TriviallyAvailable,848 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) = default);849 850_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(851 _Trait::_Available,852 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) noexcept(853 __all<is_nothrow_move_constructible_v<_Types>...>::value) : __move_constructor(__valueless_t{}) {854 this->__generic_construct(*this, std::move(__that));855 } _LIBCPP_EAT_SEMICOLON);856 857_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(858 _Trait::_Unavailable,859 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&&) = delete);860 861# undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR862 863template <class _Traits, _Trait = _Traits::__copy_constructible_trait>864class __copy_constructor;865 866# define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait, copy_constructor_definition) \867 template <class... _Types> \868 class __copy_constructor<__traits<_Types...>, copy_constructible_trait> \869 : public __move_constructor<__traits<_Types...>> { \870 using __base_type _LIBCPP_NODEBUG = __move_constructor<__traits<_Types...>>; \871 \872 public: \873 using __base_type::__base_type; \874 using __base_type::operator=; \875 \876 _LIBCPP_HIDE_FROM_ABI __copy_constructor(__copy_constructor&&) = default; \877 _LIBCPP_HIDE_FROM_ABI ~__copy_constructor() = default; \878 _LIBCPP_HIDE_FROM_ABI __copy_constructor& operator=(const __copy_constructor&) = default; \879 _LIBCPP_HIDE_FROM_ABI __copy_constructor& operator=(__copy_constructor&&) = default; \880 copy_constructor_definition; \881 }882 883_LIBCPP_VARIANT_COPY_CONSTRUCTOR(884 _Trait::_TriviallyAvailable,885 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor& __that) = default);886 887_LIBCPP_VARIANT_COPY_CONSTRUCTOR(888 _Trait::_Available,889 _LIBCPP_HIDE_FROM_ABI890 _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor& __that) : __copy_constructor(891 __valueless_t{}) { this->__generic_construct(*this, __that); } _LIBCPP_EAT_SEMICOLON);892 893_LIBCPP_VARIANT_COPY_CONSTRUCTOR(894 _Trait::_Unavailable,895 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor&) = delete);896 897# undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR898 899template <class _Traits>900class __assignment : public __copy_constructor<_Traits> {901 using __base_type _LIBCPP_NODEBUG = __copy_constructor<_Traits>;902 903public:904 using __base_type::__base_type;905 using __base_type::operator=;906 907 template <size_t _Ip, class... _Args>908 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto& __emplace(_Args&&... __args) {909 this->__destroy();910 std::__construct_at(std::addressof(this->__data), in_place_index<_Ip>, std::forward<_Args>(__args)...);911 this->__index = _Ip;912 return __access::__base::__get_alt<_Ip>(*this).__value;913 }914 915protected:916 template <size_t _Ip, class _Tp, class _Arg>917 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) {918 if (this->index() == _Ip) {919 __a.__value = std::forward<_Arg>(__arg);920 } else {921 struct {922 _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(true_type) const {923 __this->__emplace<_Ip>(std::forward<_Arg>(__arg));924 }925 _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(false_type) const {926 __this->__emplace<_Ip>(_Tp(std::forward<_Arg>(__arg)));927 }928 __assignment* __this;929 _Arg&& __arg;930 } __impl{this, std::forward<_Arg>(__arg)};931 __impl(bool_constant < is_nothrow_constructible_v<_Tp, _Arg> || !is_nothrow_move_constructible_v < _Tp >> {});932 }933 }934 935 template <class _That>936 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_assign(_That&& __that) {937 if (this->valueless_by_exception() && __that.valueless_by_exception()) {938 // do nothing.939 } else if (__that.valueless_by_exception()) {940 this->__destroy();941 } else {942 __visitation::__base::__visit_alt_at(943 __that.index(),944 [this](auto& __this_alt, auto&& __that_alt) {945 this->__assign_alt(__this_alt, std::forward<decltype(__that_alt)>(__that_alt).__value);946 },947 *this,948 std::forward<_That>(__that));949 }950 }951};952 953template <class _Traits, _Trait = _Traits::__move_assignable_trait>954class __move_assignment;955 956# define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait, move_assignment_definition) \957 template <class... _Types> \958 class __move_assignment<__traits<_Types...>, move_assignable_trait> : public __assignment<__traits<_Types...>> { \959 using __base_type _LIBCPP_NODEBUG = __assignment<__traits<_Types...>>; \960 \961 public: \962 using __base_type::__base_type; \963 using __base_type::operator=; \964 \965 _LIBCPP_HIDE_FROM_ABI __move_assignment(const __move_assignment&) = default; \966 _LIBCPP_HIDE_FROM_ABI __move_assignment(__move_assignment&&) = default; \967 _LIBCPP_HIDE_FROM_ABI ~__move_assignment() = default; \968 _LIBCPP_HIDE_FROM_ABI __move_assignment& operator=(const __move_assignment&) = default; \969 move_assignment_definition; \970 }971 972_LIBCPP_VARIANT_MOVE_ASSIGNMENT(_Trait::_TriviallyAvailable,973 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=(974 __move_assignment&& __that) = default);975 976_LIBCPP_VARIANT_MOVE_ASSIGNMENT(977 _Trait::_Available,978 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment&979 operator=(__move_assignment&& __that) noexcept(980 __all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_move_assignable_v<_Types>)...>::value) {981 this->__generic_assign(std::move(__that));982 return *this;983 } _LIBCPP_EAT_SEMICOLON);984 985_LIBCPP_VARIANT_MOVE_ASSIGNMENT(986 _Trait::_Unavailable,987 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=(__move_assignment&&) = delete);988 989# undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT990 991template <class _Traits, _Trait = _Traits::__copy_assignable_trait>992class __copy_assignment;993 994# define _LIBCPP_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait, copy_assignment_definition) \995 template <class... _Types> \996 class __copy_assignment<__traits<_Types...>, copy_assignable_trait> \997 : public __move_assignment<__traits<_Types...>> { \998 using __base_type _LIBCPP_NODEBUG = __move_assignment<__traits<_Types...>>; \999 \1000 public: \1001 using __base_type::__base_type; \1002 using __base_type::operator=; \1003 \1004 _LIBCPP_HIDE_FROM_ABI __copy_assignment(const __copy_assignment&) = default; \1005 _LIBCPP_HIDE_FROM_ABI __copy_assignment(__copy_assignment&&) = default; \1006 _LIBCPP_HIDE_FROM_ABI ~__copy_assignment() = default; \1007 _LIBCPP_HIDE_FROM_ABI __copy_assignment& operator=(__copy_assignment&&) = default; \1008 copy_assignment_definition; \1009 }1010 1011_LIBCPP_VARIANT_COPY_ASSIGNMENT(_Trait::_TriviallyAvailable,1012 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment& operator=(1013 const __copy_assignment& __that) = default);1014 1015_LIBCPP_VARIANT_COPY_ASSIGNMENT(1016 _Trait::_Available,1017 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment&1018 operator=(const __copy_assignment& __that) {1019 this->__generic_assign(__that);1020 return *this;1021 } _LIBCPP_EAT_SEMICOLON);1022 1023_LIBCPP_VARIANT_COPY_ASSIGNMENT(_Trait::_Unavailable,1024 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment& operator=(1025 const __copy_assignment&) = delete);1026 1027# undef _LIBCPP_VARIANT_COPY_ASSIGNMENT1028 1029template <class... _Types>1030class __impl : public __copy_assignment<__traits<_Types...>> {1031 using __base_type _LIBCPP_NODEBUG = __copy_assignment<__traits<_Types...>>;1032 1033public:1034 using __base_type::__base_type; // get in_place_index_t constructor & friends1035 _LIBCPP_HIDE_FROM_ABI __impl(__impl const&) = default;1036 _LIBCPP_HIDE_FROM_ABI __impl(__impl&&) = default;1037 _LIBCPP_HIDE_FROM_ABI __impl& operator=(__impl const&) = default;1038 _LIBCPP_HIDE_FROM_ABI __impl& operator=(__impl&&) = default;1039 1040 template <size_t _Ip, class _Arg>1041 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign(_Arg&& __arg) {1042 this->__assign_alt(__access::__base::__get_alt<_Ip>(*this), std::forward<_Arg>(__arg));1043 }1044 1045 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __swap(__impl& __that) {1046 if (this->valueless_by_exception() && __that.valueless_by_exception()) {1047 // do nothing.1048 } else if (this->index() == __that.index()) {1049 __visitation::__base::__visit_alt_at(1050 this->index(),1051 [](auto& __this_alt, auto& __that_alt) {1052 using std::swap;1053 swap(__this_alt.__value, __that_alt.__value);1054 },1055 *this,1056 __that);1057 } else {1058 __impl* __lhs = this;1059 __impl* __rhs = std::addressof(__that);1060 if (__lhs->__move_nothrow() && !__rhs->__move_nothrow()) {1061 std::swap(__lhs, __rhs);1062 }1063 __impl __tmp(std::move(*__rhs));1064# if _LIBCPP_HAS_EXCEPTIONS1065 if constexpr (__all<is_nothrow_move_constructible_v<_Types>...>::value) {1066 this->__generic_construct(*__rhs, std::move(*__lhs));1067 } else {1068 // EXTENSION: When the move construction of `__lhs` into `__rhs` throws1069 // and `__tmp` is nothrow move constructible then we move `__tmp` back1070 // into `__rhs` and provide the strong exception safety guarantee.1071 try {1072 this->__generic_construct(*__rhs, std::move(*__lhs));1073 } catch (...) {1074 if (__tmp.__move_nothrow()) {1075 this->__generic_construct(*__rhs, std::move(__tmp));1076 }1077 throw;1078 }1079 }1080# else1081 // this isn't consolidated with the `if constexpr` branch above due to1082 // `throw` being ill-formed with exceptions disabled even when discarded.1083 this->__generic_construct(*__rhs, std::move(*__lhs));1084# endif1085 this->__generic_construct(*__lhs, std::move(__tmp));1086 }1087 }1088 1089private:1090 constexpr inline _LIBCPP_HIDE_FROM_ABI bool __move_nothrow() const {1091 constexpr bool __results[] = {is_nothrow_move_constructible_v<_Types>...};1092 return this->valueless_by_exception() || __results[this->index()];1093 }1094};1095 1096struct __no_narrowing_check {1097 template <class _Dest, class _Source>1098 using _Apply _LIBCPP_NODEBUG = __type_identity<_Dest>;1099};1100 1101struct __narrowing_check {1102 template <class _Dest>1103 static auto __test_impl(_Dest (&&)[1]) -> __type_identity<_Dest>;1104 template <class _Dest, class _Source>1105 using _Apply _LIBCPP_NODEBUG = decltype(__test_impl<_Dest>({std::declval<_Source>()}));1106};1107 1108template <class _Dest, class _Source>1109using __check_for_narrowing _LIBCPP_NODEBUG =1110 typename _If< is_arithmetic<_Dest>::value, __narrowing_check, __no_narrowing_check >::template _Apply<_Dest,1111 _Source>;1112 1113template <class _Tp, size_t _Idx>1114struct __overload {1115 template <class _Up>1116 auto operator()(_Tp, _Up&&) const -> __check_for_narrowing<_Tp, _Up>;1117};1118 1119template <class... _Bases>1120struct __all_overloads : _Bases... {1121 void operator()() const;1122 using _Bases::operator()...;1123};1124 1125template <class _IdxSeq>1126struct __make_overloads_imp;1127 1128template <size_t... _Idx>1129struct __make_overloads_imp<index_sequence<_Idx...> > {1130 template <class... _Types>1131 using _Apply _LIBCPP_NODEBUG = __all_overloads<__overload<_Types, _Idx>...>;1132};1133 1134template <class... _Types>1135using _MakeOverloads _LIBCPP_NODEBUG =1136 typename __make_overloads_imp<make_index_sequence<sizeof...(_Types)>>::template _Apply<_Types...>;1137 1138template <class _Tp, class... _Types>1139using __best_match_t _LIBCPP_NODEBUG = typename invoke_result_t<_MakeOverloads<_Types...>, _Tp, _Tp>::type;1140 1141} // namespace __variant_detail1142 1143template <class _Visitor, class... _Vs, typename = void_t<decltype(std::__as_variant(std::declval<_Vs>()))...>>1144_LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs);1145 1146# if _LIBCPP_STD_VER >= 201147template <class _Rp,1148 class _Visitor,1149 class... _Vs,1150 typename = void_t<decltype(std::__as_variant(std::declval<_Vs>()))...>>1151_LIBCPP_HIDE_FROM_ABI constexpr _Rp visit(_Visitor&& __visitor, _Vs&&... __vs);1152# endif1153 1154template <class... _Types>1155class _LIBCPP_DECLSPEC_EMPTY_BASES _LIBCPP_NO_SPECIALIZATIONS variant1156 : private __sfinae_ctor_base< __all<is_copy_constructible_v<_Types>...>::value,1157 __all<is_move_constructible_v<_Types>...>::value>,1158 private __sfinae_assign_base<1159 __all<(is_copy_constructible_v<_Types> && is_copy_assignable_v<_Types>)...>::value,1160 __all<(is_move_constructible_v<_Types> && is_move_assignable_v<_Types>)...>::value> {1161 static_assert(0 < sizeof...(_Types), "variant must consist of at least one alternative.");1162 1163 static_assert(__all<!is_array_v<_Types>...>::value, "variant can not have an array type as an alternative.");1164 1165 static_assert(__all<!is_reference_v<_Types>...>::value, "variant can not have a reference type as an alternative.");1166 1167 static_assert(__all<!is_void_v<_Types>...>::value, "variant can not have a void type as an alternative.");1168 1169 using __first_type _LIBCPP_NODEBUG = variant_alternative_t<0, variant>;1170 1171public:1172 using __trivially_relocatable _LIBCPP_NODEBUG =1173 conditional_t<_And<__libcpp_is_trivially_relocatable<_Types>...>::value, variant, void>;1174 1175 template <bool _Dummy = true,1176 enable_if_t<__dependent_type<is_default_constructible<__first_type>, _Dummy>::value, int> = 0>1177 _LIBCPP_HIDE_FROM_ABI constexpr variant() noexcept(is_nothrow_default_constructible_v<__first_type>)1178 : __impl_(in_place_index<0>) {}1179 1180 _LIBCPP_HIDE_FROM_ABI constexpr variant(const variant&) = default;1181 _LIBCPP_HIDE_FROM_ABI constexpr variant(variant&&) = default;1182 1183 template < class _Arg,1184 enable_if_t<!is_same_v<__remove_cvref_t<_Arg>, variant>, int> = 0,1185 enable_if_t<!__is_inplace_type<__remove_cvref_t<_Arg>>::value, int> = 0,1186 enable_if_t<!__is_inplace_index<__remove_cvref_t<_Arg>>::value, int> = 0,1187 class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,1188 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,1189 enable_if_t<is_constructible_v<_Tp, _Arg>, int> = 0>1190 _LIBCPP_HIDE_FROM_ABI constexpr variant(_Arg&& __arg) noexcept(is_nothrow_constructible_v<_Tp, _Arg>)1191 : __impl_(in_place_index<_Ip>, std::forward<_Arg>(__arg)) {}1192 1193 template <size_t _Ip,1194 class... _Args,1195 class = enable_if_t<(_Ip < sizeof...(_Types)), int>,1196 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,1197 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>1198 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(in_place_index_t<_Ip>, _Args&&... __args) noexcept(1199 is_nothrow_constructible_v<_Tp, _Args...>)1200 : __impl_(in_place_index<_Ip>, std::forward<_Args>(__args)...) {}1201 1202 template < size_t _Ip,1203 class _Up,1204 class... _Args,1205 enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,1206 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,1207 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0>1208 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(1209 in_place_index_t<_Ip>,1210 initializer_list<_Up> __il,1211 _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>)1212 : __impl_(in_place_index<_Ip>, __il, std::forward<_Args>(__args)...) {}1213 1214 template < class _Tp,1215 class... _Args,1216 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,1217 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>1218 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(in_place_type_t<_Tp>, _Args&&... __args) noexcept(1219 is_nothrow_constructible_v<_Tp, _Args...>)1220 : __impl_(in_place_index<_Ip>, std::forward<_Args>(__args)...) {}1221 1222 template < class _Tp,1223 class _Up,1224 class... _Args,1225 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,1226 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0>1227 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(1228 in_place_type_t<_Tp>,1229 initializer_list<_Up> __il,1230 _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, initializer_list< _Up>&, _Args...>)1231 : __impl_(in_place_index<_Ip>, __il, std::forward<_Args>(__args)...) {}1232 1233 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~variant() = default;1234 1235 _LIBCPP_HIDE_FROM_ABI constexpr variant& operator=(const variant&) = default;1236 _LIBCPP_HIDE_FROM_ABI constexpr variant& operator=(variant&&) = default;1237 1238 template < class _Arg,1239 enable_if_t<!is_same_v<__remove_cvref_t<_Arg>, variant>, int> = 0,1240 class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,1241 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,1242 enable_if_t<is_assignable_v<_Tp&, _Arg> && is_constructible_v<_Tp, _Arg>, int> = 0>1243 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 variant&1244 operator=(_Arg&& __arg) noexcept(is_nothrow_assignable_v<_Tp&, _Arg> && is_nothrow_constructible_v<_Tp, _Arg>) {1245 __impl_.template __assign<_Ip>(std::forward<_Arg>(__arg));1246 return *this;1247 }1248 1249 template < size_t _Ip,1250 class... _Args,1251 enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,1252 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,1253 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>1254 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(_Args&&... __args) {1255 return __impl_.template __emplace<_Ip>(std::forward<_Args>(__args)...);1256 }1257 1258 template < size_t _Ip,1259 class _Up,1260 class... _Args,1261 enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,1262 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,1263 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0>1264 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {1265 return __impl_.template __emplace<_Ip>(__il, std::forward<_Args>(__args)...);1266 }1267 1268 template < class _Tp,1269 class... _Args,1270 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,1271 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>1272 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(_Args&&... __args) {1273 return __impl_.template __emplace<_Ip>(std::forward<_Args>(__args)...);1274 }1275 1276 template < class _Tp,1277 class _Up,1278 class... _Args,1279 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,1280 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0>1281 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {1282 return __impl_.template __emplace<_Ip>(__il, std::forward<_Args>(__args)...);1283 }1284 1285 _LIBCPP_HIDE_FROM_ABI constexpr bool valueless_by_exception() const noexcept {1286 return __impl_.valueless_by_exception();1287 }1288 1289 _LIBCPP_HIDE_FROM_ABI constexpr size_t index() const noexcept { return __impl_.index(); }1290 1291 template < bool _Dummy = true,1292 enable_if_t< __all<(__dependent_type<is_move_constructible<_Types>, _Dummy>::value &&1293 __dependent_type<is_swappable<_Types>, _Dummy>::value)...>::value,1294 int> = 0>1295 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(variant& __that) noexcept(1296 __all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_swappable_v<_Types>)...>::value) {1297 __impl_.__swap(__that.__impl_);1298 }1299 1300# if _LIBCPP_STD_VER >= 261301 // Helper class to implement [variant.visit]/101302 // Constraints: The call to visit does not use an explicit template-argument-list1303 // that begins with a type template-argument.1304 struct __variant_visit_barrier_tag {1305 _LIBCPP_HIDE_FROM_ABI explicit __variant_visit_barrier_tag() = default;1306 };1307 1308 template <__variant_visit_barrier_tag = __variant_visit_barrier_tag{}, class _Self, class _Visitor>1309 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) visit(this _Self&& __self, _Visitor&& __visitor) {1310 return std::visit(std::forward<_Visitor>(__visitor), std::__forward_as<_Self, variant>(__self));1311 }1312 1313 template <class _Rp, class _Self, class _Visitor>1314 _LIBCPP_HIDE_FROM_ABI constexpr _Rp visit(this _Self&& __self, _Visitor&& __visitor) {1315 return std::visit<_Rp>(std::forward<_Visitor>(__visitor), std::__forward_as<_Self, variant>(__self));1316 }1317# endif1318 1319private:1320 __variant_detail::__impl<_Types...> __impl_;1321 1322 friend struct __variant_detail::__access::__variant;1323 friend struct __variant_detail::__visitation::__variant;1324};1325 1326template <size_t _Ip, class... _Types>1327_LIBCPP_HIDE_FROM_ABI constexpr bool __holds_alternative(const variant<_Types...>& __v) noexcept {1328 return __v.index() == _Ip;1329}1330 1331template <class _Tp, class... _Types>1332_LIBCPP_HIDE_FROM_ABI constexpr bool holds_alternative(const variant<_Types...>& __v) noexcept {1333 return std::__holds_alternative<__find_exactly_one_t<_Tp, _Types...>::value>(__v);1334}1335 1336template <size_t _Ip, class _Vp>1337_LIBCPP_HIDE_FROM_ABI constexpr auto&& __generic_get(_Vp&& __v) {1338 using __variant_detail::__access::__variant;1339 if (!std::__holds_alternative<_Ip>(__v)) {1340 std::__throw_bad_variant_access();1341 }1342 return __variant::__get_alt<_Ip>(std::forward<_Vp>(__v)).__value;1343}1344 1345template <size_t _Ip, class... _Types>1346_LIBCPP_HIDE_FROM_ABI constexpr variant_alternative_t<_Ip, variant<_Types...>>& get(variant<_Types...>& __v) {1347 static_assert(_Ip < sizeof...(_Types));1348 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);1349 return std::__generic_get<_Ip>(__v);1350}1351 1352template <size_t _Ip, class... _Types>1353_LIBCPP_HIDE_FROM_ABI constexpr variant_alternative_t<_Ip, variant<_Types...>>&& get(variant<_Types...>&& __v) {1354 static_assert(_Ip < sizeof...(_Types));1355 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);1356 return std::__generic_get<_Ip>(std::move(__v));1357}1358 1359template <size_t _Ip, class... _Types>1360_LIBCPP_HIDE_FROM_ABI constexpr const variant_alternative_t<_Ip, variant<_Types...>>&1361get(const variant<_Types...>& __v) {1362 static_assert(_Ip < sizeof...(_Types));1363 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);1364 return std::__generic_get<_Ip>(__v);1365}1366 1367template <size_t _Ip, class... _Types>1368_LIBCPP_HIDE_FROM_ABI constexpr const variant_alternative_t<_Ip, variant<_Types...>>&&1369get(const variant<_Types...>&& __v) {1370 static_assert(_Ip < sizeof...(_Types));1371 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);1372 return std::__generic_get<_Ip>(std::move(__v));1373}1374 1375template <class _Tp, class... _Types>1376_LIBCPP_HIDE_FROM_ABI constexpr _Tp& get(variant<_Types...>& __v) {1377 static_assert(!is_void_v<_Tp>);1378 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);1379}1380 1381template <class _Tp, class... _Types>1382_LIBCPP_HIDE_FROM_ABI constexpr _Tp&& get(variant<_Types...>&& __v) {1383 static_assert(!is_void_v<_Tp>);1384 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(std::move(__v));1385}1386 1387template <class _Tp, class... _Types>1388_LIBCPP_HIDE_FROM_ABI constexpr const _Tp& get(const variant<_Types...>& __v) {1389 static_assert(!is_void_v<_Tp>);1390 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);1391}1392 1393template <class _Tp, class... _Types>1394_LIBCPP_HIDE_FROM_ABI constexpr const _Tp&& get(const variant<_Types...>&& __v) {1395 static_assert(!is_void_v<_Tp>);1396 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(std::move(__v));1397}1398 1399template <size_t _Ip, class _Vp>1400_LIBCPP_HIDE_FROM_ABI constexpr auto* __generic_get_if(_Vp* __v) noexcept {1401 using __variant_detail::__access::__variant;1402 return __v && std::__holds_alternative<_Ip>(*__v) ? std::addressof(__variant::__get_alt<_Ip>(*__v).__value) : nullptr;1403}1404 1405template <size_t _Ip, class... _Types>1406_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<variant_alternative_t<_Ip, variant<_Types...>>>1407get_if(variant<_Types...>* __v) noexcept {1408 static_assert(_Ip < sizeof...(_Types));1409 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);1410 return std::__generic_get_if<_Ip>(__v);1411}1412 1413template <size_t _Ip, class... _Types>1414_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<const variant_alternative_t<_Ip, variant<_Types...>>>1415get_if(const variant<_Types...>* __v) noexcept {1416 static_assert(_Ip < sizeof...(_Types));1417 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);1418 return std::__generic_get_if<_Ip>(__v);1419}1420 1421template <class _Tp, class... _Types>1422_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<_Tp> get_if(variant<_Types...>* __v) noexcept {1423 static_assert(!is_void_v<_Tp>);1424 return std::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);1425}1426 1427template <class _Tp, class... _Types>1428_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<const _Tp> get_if(const variant<_Types...>* __v) noexcept {1429 static_assert(!is_void_v<_Tp>);1430 return std::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);1431}1432 1433template <class _Operator>1434struct __convert_to_bool {1435 template <class _T1, class _T2>1436 _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(_T1&& __t1, _T2&& __t2) const {1437 static_assert(is_convertible<decltype(_Operator{}(std::forward<_T1>(__t1), std::forward<_T2>(__t2))), bool>::value,1438 "the relational operator does not return a type which is implicitly convertible to bool");1439 return _Operator{}(std::forward<_T1>(__t1), std::forward<_T2>(__t2));1440 }1441};1442 1443template <class... _Types>1444# if _LIBCPP_STD_VER >= 261445 requires(requires(const _Types& __t) {1446 { __t == __t } -> __core_convertible_to<bool>;1447 } && ...)1448# endif1449_LIBCPP_HIDE_FROM_ABI constexpr bool operator==(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {1450 using __variant_detail::__visitation::__variant;1451 if (__lhs.index() != __rhs.index())1452 return false;1453 if (__lhs.valueless_by_exception())1454 return true;1455 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<equal_to<>>{}, __lhs, __rhs);1456}1457 1458# if _LIBCPP_STD_VER >= 201459 1460template <class... _Types>1461 requires(three_way_comparable<_Types> && ...)1462_LIBCPP_HIDE_FROM_ABI constexpr common_comparison_category_t<compare_three_way_result_t<_Types>...>1463operator<=>(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {1464 using __variant_detail::__visitation::__variant;1465 using __result_t = common_comparison_category_t<compare_three_way_result_t<_Types>...>;1466 if (__lhs.valueless_by_exception() && __rhs.valueless_by_exception())1467 return strong_ordering::equal;1468 if (__lhs.valueless_by_exception())1469 return strong_ordering::less;1470 if (__rhs.valueless_by_exception())1471 return strong_ordering::greater;1472 if (auto __c = __lhs.index() <=> __rhs.index(); __c != 0)1473 return __c;1474 auto __three_way = []<class _Type>(const _Type& __v, const _Type& __w) -> __result_t { return __v <=> __w; };1475 return __variant::__visit_value_at(__lhs.index(), __three_way, __lhs, __rhs);1476}1477 1478# endif // _LIBCPP_STD_VER >= 201479 1480template <class... _Types>1481# if _LIBCPP_STD_VER >= 261482 requires(requires(const _Types& __t) {1483 { __t != __t } -> __core_convertible_to<bool>;1484 } && ...)1485# endif1486_LIBCPP_HIDE_FROM_ABI constexpr bool operator!=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {1487 using __variant_detail::__visitation::__variant;1488 if (__lhs.index() != __rhs.index())1489 return true;1490 if (__lhs.valueless_by_exception())1491 return false;1492 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<not_equal_to<>>{}, __lhs, __rhs);1493}1494 1495template <class... _Types>1496# if _LIBCPP_STD_VER >= 261497 requires(requires(const _Types& __t) {1498 { __t < __t } -> __core_convertible_to<bool>;1499 } && ...)1500# endif1501_LIBCPP_HIDE_FROM_ABI constexpr bool operator<(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {1502 using __variant_detail::__visitation::__variant;1503 if (__rhs.valueless_by_exception())1504 return false;1505 if (__lhs.valueless_by_exception())1506 return true;1507 if (__lhs.index() < __rhs.index())1508 return true;1509 if (__lhs.index() > __rhs.index())1510 return false;1511 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<less<>>{}, __lhs, __rhs);1512}1513 1514template <class... _Types>1515# if _LIBCPP_STD_VER >= 261516 requires(requires(const _Types& __t) {1517 { __t > __t } -> __core_convertible_to<bool>;1518 } && ...)1519# endif1520_LIBCPP_HIDE_FROM_ABI constexpr bool operator>(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {1521 using __variant_detail::__visitation::__variant;1522 if (__lhs.valueless_by_exception())1523 return false;1524 if (__rhs.valueless_by_exception())1525 return true;1526 if (__lhs.index() > __rhs.index())1527 return true;1528 if (__lhs.index() < __rhs.index())1529 return false;1530 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<greater<>>{}, __lhs, __rhs);1531}1532 1533template <class... _Types>1534# if _LIBCPP_STD_VER >= 261535 requires(requires(const _Types& __t) {1536 { __t <= __t } -> __core_convertible_to<bool>;1537 } && ...)1538# endif1539_LIBCPP_HIDE_FROM_ABI constexpr bool operator<=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {1540 using __variant_detail::__visitation::__variant;1541 if (__lhs.valueless_by_exception())1542 return true;1543 if (__rhs.valueless_by_exception())1544 return false;1545 if (__lhs.index() < __rhs.index())1546 return true;1547 if (__lhs.index() > __rhs.index())1548 return false;1549 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<less_equal<>>{}, __lhs, __rhs);1550}1551 1552template <class... _Types>1553# if _LIBCPP_STD_VER >= 261554 requires(requires(const _Types& __t) {1555 { __t >= __t } -> __core_convertible_to<bool>;1556 } && ...)1557# endif1558_LIBCPP_HIDE_FROM_ABI constexpr bool operator>=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {1559 using __variant_detail::__visitation::__variant;1560 if (__rhs.valueless_by_exception())1561 return true;1562 if (__lhs.valueless_by_exception())1563 return false;1564 if (__lhs.index() > __rhs.index())1565 return true;1566 if (__lhs.index() < __rhs.index())1567 return false;1568 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<greater_equal<>>{}, __lhs, __rhs);1569}1570 1571template <class... _Vs>1572_LIBCPP_HIDE_FROM_ABI constexpr void __throw_if_valueless(_Vs&&... __vs) {1573 const bool __valueless = (... || std::__as_variant(__vs).valueless_by_exception());1574 if (__valueless) {1575 std::__throw_bad_variant_access();1576 }1577}1578 1579template < class _Visitor, class... _Vs, typename>1580_LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs) {1581 using __variant_detail::__visitation::__variant;1582 std::__throw_if_valueless(std::forward<_Vs>(__vs)...);1583 return __variant::__visit_value(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs)...);1584}1585 1586# if _LIBCPP_STD_VER >= 201587template < class _Rp, class _Visitor, class... _Vs, typename>1588_LIBCPP_HIDE_FROM_ABI constexpr _Rp visit(_Visitor&& __visitor, _Vs&&... __vs) {1589 using __variant_detail::__visitation::__variant;1590 std::__throw_if_valueless(std::forward<_Vs>(__vs)...);1591 return __variant::__visit_value<_Rp>(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs)...);1592}1593# endif1594 1595template <class... _Types>1596_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto1597swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs) noexcept(noexcept(__lhs.swap(__rhs)))1598 -> decltype(__lhs.swap(__rhs)) {1599 return __lhs.swap(__rhs);1600}1601 1602template <class... _Types>1603struct hash< __enable_hash_helper<variant<_Types...>, remove_const_t<_Types>...>> {1604# if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)1605 using argument_type _LIBCPP_DEPRECATED_IN_CXX17 = variant<_Types...>;1606 using result_type _LIBCPP_DEPRECATED_IN_CXX17 = size_t;1607# endif1608 1609 _LIBCPP_HIDE_FROM_ABI size_t operator()(const variant<_Types...>& __v) const {1610 using __variant_detail::__visitation::__variant;1611 size_t __res =1612 __v.valueless_by_exception()1613 ? 299792458 // Random value chosen by the universe upon creation1614 : __variant::__visit_alt(1615 [](const auto& __alt) {1616 using __alt_type = __remove_cvref_t<decltype(__alt)>;1617 using __value_type = remove_const_t< typename __alt_type::__value_type>;1618 return hash<__value_type>{}(__alt.__value);1619 },1620 __v);1621 return std::__hash_combine(__res, hash<size_t>{}(__v.index()));1622 }1623};1624 1625// __unchecked_get is the same as std::get, except, it is UB to use it with the wrong1626// type whereas std::get will throw or returning nullptr. This makes it faster than1627// std::get.1628template <size_t _Ip, class _Vp>1629_LIBCPP_HIDE_FROM_ABI constexpr auto&& __unchecked_get(_Vp&& __v) noexcept {1630 using __variant_detail::__access::__variant;1631 return __variant::__get_alt<_Ip>(std::forward<_Vp>(__v)).__value;1632}1633 1634template <class _Tp, class... _Types>1635_LIBCPP_HIDE_FROM_ABI constexpr auto&& __unchecked_get(const variant<_Types...>& __v) noexcept {1636 return std::__unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);1637}1638 1639template <class _Tp, class... _Types>1640_LIBCPP_HIDE_FROM_ABI constexpr auto&& __unchecked_get(variant<_Types...>& __v) noexcept {1641 return std::__unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);1642}1643 1644# endif // _LIBCPP_STD_VER >= 171645 1646_LIBCPP_END_NAMESPACE_STD1647 1648_LIBCPP_POP_MACROS1649 1650# if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 201651# include <cstddef>1652# include <exception>1653# include <tuple>1654# include <type_traits>1655# include <typeinfo>1656# include <utility>1657# endif1658#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)1659 1660#endif // _LIBCPP_VARIANT1661