xref: /freebsd/contrib/llvm-project/libcxx/include/variant (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
10b57cec5SDimitry Andric// -*- C++ -*-
2349cc55cSDimitry Andric//===----------------------------------------------------------------------===//
30b57cec5SDimitry Andric//
40b57cec5SDimitry Andric// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
50b57cec5SDimitry Andric// See https://llvm.org/LICENSE.txt for license information.
60b57cec5SDimitry Andric// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
70b57cec5SDimitry Andric//
80b57cec5SDimitry Andric//===----------------------------------------------------------------------===//
90b57cec5SDimitry Andric
100b57cec5SDimitry Andric#ifndef _LIBCPP_VARIANT
110b57cec5SDimitry Andric#define _LIBCPP_VARIANT
120b57cec5SDimitry Andric
130b57cec5SDimitry Andric/*
140b57cec5SDimitry Andric   variant synopsis
150b57cec5SDimitry Andric
160b57cec5SDimitry Andricnamespace std {
170b57cec5SDimitry Andric
180b57cec5SDimitry Andric  // 20.7.2, class template variant
190b57cec5SDimitry Andric  template <class... Types>
200b57cec5SDimitry Andric  class variant {
210b57cec5SDimitry Andric  public:
220b57cec5SDimitry Andric
230b57cec5SDimitry Andric    // 20.7.2.1, constructors
240b57cec5SDimitry Andric    constexpr variant() noexcept(see below);
25bdd1243dSDimitry Andric    constexpr variant(const variant&);
26bdd1243dSDimitry Andric    constexpr variant(variant&&) noexcept(see below);
270b57cec5SDimitry Andric
280b57cec5SDimitry Andric    template <class T> constexpr variant(T&&) noexcept(see below);
290b57cec5SDimitry Andric
300b57cec5SDimitry Andric    template <class T, class... Args>
310b57cec5SDimitry Andric    constexpr explicit variant(in_place_type_t<T>, Args&&...);
320b57cec5SDimitry Andric
330b57cec5SDimitry Andric    template <class T, class U, class... Args>
340b57cec5SDimitry Andric    constexpr explicit variant(
350b57cec5SDimitry Andric        in_place_type_t<T>, initializer_list<U>, Args&&...);
360b57cec5SDimitry Andric
370b57cec5SDimitry Andric    template <size_t I, class... Args>
380b57cec5SDimitry Andric    constexpr explicit variant(in_place_index_t<I>, Args&&...);
390b57cec5SDimitry Andric
400b57cec5SDimitry Andric    template <size_t I, class U, class... Args>
410b57cec5SDimitry Andric    constexpr explicit variant(
420b57cec5SDimitry Andric        in_place_index_t<I>, initializer_list<U>, Args&&...);
430b57cec5SDimitry Andric
440b57cec5SDimitry Andric    // 20.7.2.2, destructor
450b57cec5SDimitry Andric    ~variant();
460b57cec5SDimitry Andric
470b57cec5SDimitry Andric    // 20.7.2.3, assignment
48bdd1243dSDimitry Andric    constexpr variant& operator=(const variant&);
49bdd1243dSDimitry Andric    constexpr variant& operator=(variant&&) noexcept(see below);
500b57cec5SDimitry Andric
510b57cec5SDimitry Andric    template <class T> variant& operator=(T&&) noexcept(see below);
520b57cec5SDimitry Andric
530b57cec5SDimitry Andric    // 20.7.2.4, modifiers
540b57cec5SDimitry Andric    template <class T, class... Args>
550b57cec5SDimitry Andric    T& emplace(Args&&...);
560b57cec5SDimitry Andric
570b57cec5SDimitry Andric    template <class T, class U, class... Args>
580b57cec5SDimitry Andric    T& emplace(initializer_list<U>, Args&&...);
590b57cec5SDimitry Andric
600b57cec5SDimitry Andric    template <size_t I, class... Args>
610b57cec5SDimitry Andric    variant_alternative_t<I, variant>& emplace(Args&&...);
620b57cec5SDimitry Andric
630b57cec5SDimitry Andric    template <size_t I, class U, class...  Args>
640b57cec5SDimitry Andric    variant_alternative_t<I, variant>& emplace(initializer_list<U>, Args&&...);
650b57cec5SDimitry Andric
660b57cec5SDimitry Andric    // 20.7.2.5, value status
670b57cec5SDimitry Andric    constexpr bool valueless_by_exception() const noexcept;
680b57cec5SDimitry Andric    constexpr size_t index() const noexcept;
690b57cec5SDimitry Andric
700b57cec5SDimitry Andric    // 20.7.2.6, swap
710b57cec5SDimitry Andric    void swap(variant&) noexcept(see below);
720b57cec5SDimitry Andric  };
730b57cec5SDimitry Andric
740b57cec5SDimitry Andric  // 20.7.3, variant helper classes
750b57cec5SDimitry Andric  template <class T> struct variant_size; // undefined
760b57cec5SDimitry Andric
770b57cec5SDimitry Andric  template <class T>
780b57cec5SDimitry Andric  inline constexpr size_t variant_size_v = variant_size<T>::value;
790b57cec5SDimitry Andric
800b57cec5SDimitry Andric  template <class T> struct variant_size<const T>;
810b57cec5SDimitry Andric  template <class T> struct variant_size<volatile T>;
820b57cec5SDimitry Andric  template <class T> struct variant_size<const volatile T>;
830b57cec5SDimitry Andric
840b57cec5SDimitry Andric  template <class... Types>
850b57cec5SDimitry Andric  struct variant_size<variant<Types...>>;
860b57cec5SDimitry Andric
870b57cec5SDimitry Andric  template <size_t I, class T> struct variant_alternative; // undefined
880b57cec5SDimitry Andric
890b57cec5SDimitry Andric  template <size_t I, class T>
900b57cec5SDimitry Andric  using variant_alternative_t = typename variant_alternative<I, T>::type;
910b57cec5SDimitry Andric
920b57cec5SDimitry Andric  template <size_t I, class T> struct variant_alternative<I, const T>;
930b57cec5SDimitry Andric  template <size_t I, class T> struct variant_alternative<I, volatile T>;
940b57cec5SDimitry Andric  template <size_t I, class T> struct variant_alternative<I, const volatile T>;
950b57cec5SDimitry Andric
960b57cec5SDimitry Andric  template <size_t I, class... Types>
970b57cec5SDimitry Andric  struct variant_alternative<I, variant<Types...>>;
980b57cec5SDimitry Andric
990b57cec5SDimitry Andric  inline constexpr size_t variant_npos = -1;
1000b57cec5SDimitry Andric
1010b57cec5SDimitry Andric  // 20.7.4, value access
1020b57cec5SDimitry Andric  template <class T, class... Types>
1030b57cec5SDimitry Andric  constexpr bool holds_alternative(const variant<Types...>&) noexcept;
1040b57cec5SDimitry Andric
1050b57cec5SDimitry Andric  template <size_t I, class... Types>
1060b57cec5SDimitry Andric  constexpr variant_alternative_t<I, variant<Types...>>&
1070b57cec5SDimitry Andric  get(variant<Types...>&);
1080b57cec5SDimitry Andric
1090b57cec5SDimitry Andric  template <size_t I, class... Types>
1100b57cec5SDimitry Andric  constexpr variant_alternative_t<I, variant<Types...>>&&
1110b57cec5SDimitry Andric  get(variant<Types...>&&);
1120b57cec5SDimitry Andric
1130b57cec5SDimitry Andric  template <size_t I, class... Types>
1140b57cec5SDimitry Andric  constexpr variant_alternative_t<I, variant<Types...>> const&
1150b57cec5SDimitry Andric  get(const variant<Types...>&);
1160b57cec5SDimitry Andric
1170b57cec5SDimitry Andric  template <size_t I, class... Types>
1180b57cec5SDimitry Andric  constexpr variant_alternative_t<I, variant<Types...>> const&&
1190b57cec5SDimitry Andric  get(const variant<Types...>&&);
1200b57cec5SDimitry Andric
1210b57cec5SDimitry Andric  template <class T, class...  Types>
1220b57cec5SDimitry Andric  constexpr T& get(variant<Types...>&);
1230b57cec5SDimitry Andric
1240b57cec5SDimitry Andric  template <class T, class... Types>
1250b57cec5SDimitry Andric  constexpr T&& get(variant<Types...>&&);
1260b57cec5SDimitry Andric
1270b57cec5SDimitry Andric  template <class T, class... Types>
1280b57cec5SDimitry Andric  constexpr const T& get(const variant<Types...>&);
1290b57cec5SDimitry Andric
1300b57cec5SDimitry Andric  template <class T, class... Types>
1310b57cec5SDimitry Andric  constexpr const T&& get(const variant<Types...>&&);
1320b57cec5SDimitry Andric
1330b57cec5SDimitry Andric  template <size_t I, class... Types>
1340b57cec5SDimitry Andric  constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>>
1350b57cec5SDimitry Andric  get_if(variant<Types...>*) noexcept;
1360b57cec5SDimitry Andric
1370b57cec5SDimitry Andric  template <size_t I, class... Types>
1380b57cec5SDimitry Andric  constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>>
1390b57cec5SDimitry Andric  get_if(const variant<Types...>*) noexcept;
1400b57cec5SDimitry Andric
1410b57cec5SDimitry Andric  template <class T, class... Types>
1420b57cec5SDimitry Andric  constexpr add_pointer_t<T>
1430b57cec5SDimitry Andric  get_if(variant<Types...>*) noexcept;
1440b57cec5SDimitry Andric
1450b57cec5SDimitry Andric  template <class T, class... Types>
1460b57cec5SDimitry Andric  constexpr add_pointer_t<const T>
1470b57cec5SDimitry Andric  get_if(const variant<Types...>*) noexcept;
1480b57cec5SDimitry Andric
1490b57cec5SDimitry Andric  // 20.7.5, relational operators
1500b57cec5SDimitry Andric  template <class... Types>
1510b57cec5SDimitry Andric  constexpr bool operator==(const variant<Types...>&, const variant<Types...>&);
1520b57cec5SDimitry Andric
1530b57cec5SDimitry Andric  template <class... Types>
1540b57cec5SDimitry Andric  constexpr bool operator!=(const variant<Types...>&, const variant<Types...>&);
1550b57cec5SDimitry Andric
1560b57cec5SDimitry Andric  template <class... Types>
1570b57cec5SDimitry Andric  constexpr bool operator<(const variant<Types...>&, const variant<Types...>&);
1580b57cec5SDimitry Andric
1590b57cec5SDimitry Andric  template <class... Types>
1600b57cec5SDimitry Andric  constexpr bool operator>(const variant<Types...>&, const variant<Types...>&);
1610b57cec5SDimitry Andric
1620b57cec5SDimitry Andric  template <class... Types>
1630b57cec5SDimitry Andric  constexpr bool operator<=(const variant<Types...>&, const variant<Types...>&);
1640b57cec5SDimitry Andric
1650b57cec5SDimitry Andric  template <class... Types>
1660b57cec5SDimitry Andric  constexpr bool operator>=(const variant<Types...>&, const variant<Types...>&);
1670b57cec5SDimitry Andric
168bdd1243dSDimitry Andric  template <class... Types> requires (three_way_comparable<Types> && ...)
169bdd1243dSDimitry Andric  constexpr common_comparison_category_t<compare_three_way_result_t<Types>...>
170bdd1243dSDimitry Andric    operator<=>(const variant<Types...>&, const variant<Types...>&);           // since C++20
171bdd1243dSDimitry Andric
1720b57cec5SDimitry Andric  // 20.7.6, visitation
1730b57cec5SDimitry Andric  template <class Visitor, class... Variants>
1740b57cec5SDimitry Andric  constexpr see below visit(Visitor&&, Variants&&...);
1750b57cec5SDimitry Andric
176e8d8bef9SDimitry Andric  template <class R, class Visitor, class... Variants>
177e8d8bef9SDimitry Andric  constexpr R visit(Visitor&&, Variants&&...); // since C++20
178e8d8bef9SDimitry Andric
1790b57cec5SDimitry Andric  // 20.7.7, class monostate
1800b57cec5SDimitry Andric  struct monostate;
1810b57cec5SDimitry Andric
1820b57cec5SDimitry Andric  // 20.7.8, monostate relational operators
1830b57cec5SDimitry Andric  constexpr bool operator==(monostate, monostate) noexcept;
184bdd1243dSDimitry Andric  constexpr bool operator!=(monostate, monostate) noexcept;             // until C++20
185bdd1243dSDimitry Andric  constexpr bool operator<(monostate, monostate) noexcept;              // until C++20
186bdd1243dSDimitry Andric  constexpr bool operator>(monostate, monostate) noexcept;              // until C++20
187bdd1243dSDimitry Andric  constexpr bool operator<=(monostate, monostate) noexcept;             // until C++20
188bdd1243dSDimitry Andric  constexpr bool operator>=(monostate, monostate) noexcept;             // until C++20
189bdd1243dSDimitry Andric  constexpr strong_ordering operator<=>(monostate, monostate) noexcept; // since C++20
1900b57cec5SDimitry Andric
1910b57cec5SDimitry Andric  // 20.7.9, specialized algorithms
1920b57cec5SDimitry Andric  template <class... Types>
1930b57cec5SDimitry Andric  void swap(variant<Types...>&, variant<Types...>&) noexcept(see below);
1940b57cec5SDimitry Andric
1950b57cec5SDimitry Andric  // 20.7.10, class bad_variant_access
1960b57cec5SDimitry Andric  class bad_variant_access;
1970b57cec5SDimitry Andric
1980b57cec5SDimitry Andric  // 20.7.11, hash support
1990b57cec5SDimitry Andric  template <class T> struct hash;
2000b57cec5SDimitry Andric  template <class... Types> struct hash<variant<Types...>>;
2010b57cec5SDimitry Andric  template <> struct hash<monostate>;
2020b57cec5SDimitry Andric
2030b57cec5SDimitry Andric} // namespace std
2040b57cec5SDimitry Andric
2050b57cec5SDimitry Andric*/
2060b57cec5SDimitry Andric
20781ad6265SDimitry Andric#include <__assert> // all public C++ headers provide the assertion handler
208e8d8bef9SDimitry Andric#include <__availability>
209bdd1243dSDimitry Andric#include <__compare/common_comparison_category.h>
210bdd1243dSDimitry Andric#include <__compare/compare_three_way_result.h>
211bdd1243dSDimitry Andric#include <__compare/three_way_comparable.h>
212fe6060f1SDimitry Andric#include <__config>
213*06c3fb27SDimitry Andric#include <__exception/exception.h>
214fe6060f1SDimitry Andric#include <__functional/hash.h>
215bdd1243dSDimitry Andric#include <__functional/invoke.h>
21681ad6265SDimitry Andric#include <__functional/operations.h>
21781ad6265SDimitry Andric#include <__functional/unary_function.h>
218*06c3fb27SDimitry Andric#include <__memory/addressof.h>
219bdd1243dSDimitry Andric#include <__type_traits/add_const.h>
220bdd1243dSDimitry Andric#include <__type_traits/add_cv.h>
221bdd1243dSDimitry Andric#include <__type_traits/add_pointer.h>
222bdd1243dSDimitry Andric#include <__type_traits/add_volatile.h>
223bdd1243dSDimitry Andric#include <__type_traits/dependent_type.h>
224bdd1243dSDimitry Andric#include <__type_traits/is_array.h>
225bdd1243dSDimitry Andric#include <__type_traits/is_destructible.h>
226bdd1243dSDimitry Andric#include <__type_traits/is_nothrow_move_constructible.h>
227bdd1243dSDimitry Andric#include <__type_traits/is_trivially_copy_assignable.h>
228bdd1243dSDimitry Andric#include <__type_traits/is_trivially_copy_constructible.h>
229bdd1243dSDimitry Andric#include <__type_traits/is_trivially_destructible.h>
230bdd1243dSDimitry Andric#include <__type_traits/is_trivially_move_assignable.h>
231bdd1243dSDimitry Andric#include <__type_traits/is_trivially_move_constructible.h>
232bdd1243dSDimitry Andric#include <__type_traits/is_void.h>
233bdd1243dSDimitry Andric#include <__type_traits/remove_const.h>
234bdd1243dSDimitry Andric#include <__type_traits/type_identity.h>
235bdd1243dSDimitry Andric#include <__type_traits/void_t.h>
236*06c3fb27SDimitry Andric#include <__utility/declval.h>
237fe6060f1SDimitry Andric#include <__utility/forward.h>
23881ad6265SDimitry Andric#include <__utility/in_place.h>
23981ad6265SDimitry Andric#include <__utility/move.h>
24081ad6265SDimitry Andric#include <__utility/swap.h>
241fe6060f1SDimitry Andric#include <__variant/monostate.h>
242*06c3fb27SDimitry Andric#include <__verbose_abort>
2430b57cec5SDimitry Andric#include <initializer_list>
244fe6060f1SDimitry Andric#include <limits>
2450b57cec5SDimitry Andric#include <new>
2460b57cec5SDimitry Andric#include <tuple>
2470b57cec5SDimitry Andric#include <version>
2480b57cec5SDimitry Andric
24981ad6265SDimitry Andric// standard-mandated includes
250bdd1243dSDimitry Andric
251bdd1243dSDimitry Andric// [variant.syn]
25281ad6265SDimitry Andric#include <compare>
25381ad6265SDimitry Andric
2540b57cec5SDimitry Andric#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
2550b57cec5SDimitry Andric#  pragma GCC system_header
2560b57cec5SDimitry Andric#endif
2570b57cec5SDimitry Andric
2580b57cec5SDimitry Andric_LIBCPP_PUSH_MACROS
2590b57cec5SDimitry Andric#include <__undef_macros>
2600b57cec5SDimitry Andric
2610b57cec5SDimitry Andricnamespace std { // explicitly not using versioning namespace
2620b57cec5SDimitry Andric
263*06c3fb27SDimitry Andricclass _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS bad_variant_access : public exception {
2640b57cec5SDimitry Andricpublic:
265bdd1243dSDimitry Andric   const char* what() const _NOEXCEPT override;
2660b57cec5SDimitry Andric};
2670b57cec5SDimitry Andric
2680b57cec5SDimitry Andric} // namespace std
2690b57cec5SDimitry Andric
2700b57cec5SDimitry Andric_LIBCPP_BEGIN_NAMESPACE_STD
2710b57cec5SDimitry Andric
272*06c3fb27SDimitry Andric#if _LIBCPP_STD_VER >= 17
2730b57cec5SDimitry Andric
274fe6060f1SDimitry Andric// Light N-dimensional array of function pointers. Used in place of std::array to avoid
275fe6060f1SDimitry Andric// adding a dependency.
276fe6060f1SDimitry Andrictemplate<class _Tp, size_t _Size>
277fe6060f1SDimitry Andricstruct __farray {
278fe6060f1SDimitry Andric  static_assert(_Size > 0, "N-dimensional array should never be empty in std::visit");
279fe6060f1SDimitry Andric  _Tp __buf_[_Size] = {};
280fe6060f1SDimitry Andric
281fe6060f1SDimitry Andric  _LIBCPP_INLINE_VISIBILITY constexpr
282fe6060f1SDimitry Andric  const _Tp &operator[](size_t __n) const noexcept {
283fe6060f1SDimitry Andric      return __buf_[__n];
284fe6060f1SDimitry Andric  }
285fe6060f1SDimitry Andric};
286fe6060f1SDimitry Andric
2870b57cec5SDimitry Andric_LIBCPP_NORETURN
288bdd1243dSDimitry Andricinline _LIBCPP_HIDE_FROM_ABI
2890b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
2900b57cec5SDimitry Andricvoid __throw_bad_variant_access() {
291*06c3fb27SDimitry Andric#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
2920b57cec5SDimitry Andric        throw bad_variant_access();
2930b57cec5SDimitry Andric#else
294*06c3fb27SDimitry Andric    _LIBCPP_VERBOSE_ABORT("bad_variant_access was thrown in -fno-exceptions mode");
2950b57cec5SDimitry Andric#endif
2960b57cec5SDimitry Andric}
2970b57cec5SDimitry Andric
2980b57cec5SDimitry Andrictemplate <class... _Types>
2990b57cec5SDimitry Andricclass _LIBCPP_TEMPLATE_VIS variant;
3000b57cec5SDimitry Andric
3010b57cec5SDimitry Andrictemplate <class _Tp>
3020b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_size;
3030b57cec5SDimitry Andric
3040b57cec5SDimitry Andrictemplate <class _Tp>
305349cc55cSDimitry Andricinline constexpr size_t variant_size_v = variant_size<_Tp>::value;
3060b57cec5SDimitry Andric
3070b57cec5SDimitry Andrictemplate <class _Tp>
3080b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_size<const _Tp> : variant_size<_Tp> {};
3090b57cec5SDimitry Andric
3100b57cec5SDimitry Andrictemplate <class _Tp>
3110b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_size<volatile _Tp> : variant_size<_Tp> {};
3120b57cec5SDimitry Andric
3130b57cec5SDimitry Andrictemplate <class _Tp>
3140b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_size<const volatile _Tp>
3150b57cec5SDimitry Andric    : variant_size<_Tp> {};
3160b57cec5SDimitry Andric
3170b57cec5SDimitry Andrictemplate <class... _Types>
3180b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_size<variant<_Types...>>
3190b57cec5SDimitry Andric    : integral_constant<size_t, sizeof...(_Types)> {};
3200b57cec5SDimitry Andric
3210b57cec5SDimitry Andrictemplate <size_t _Ip, class _Tp>
3220b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_alternative;
3230b57cec5SDimitry Andric
3240b57cec5SDimitry Andrictemplate <size_t _Ip, class _Tp>
3250b57cec5SDimitry Andricusing variant_alternative_t = typename variant_alternative<_Ip, _Tp>::type;
3260b57cec5SDimitry Andric
3270b57cec5SDimitry Andrictemplate <size_t _Ip, class _Tp>
3280b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const _Tp>
3290b57cec5SDimitry Andric    : add_const<variant_alternative_t<_Ip, _Tp>> {};
3300b57cec5SDimitry Andric
3310b57cec5SDimitry Andrictemplate <size_t _Ip, class _Tp>
3320b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, volatile _Tp>
3330b57cec5SDimitry Andric    : add_volatile<variant_alternative_t<_Ip, _Tp>> {};
3340b57cec5SDimitry Andric
3350b57cec5SDimitry Andrictemplate <size_t _Ip, class _Tp>
3360b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const volatile _Tp>
3370b57cec5SDimitry Andric    : add_cv<variant_alternative_t<_Ip, _Tp>> {};
3380b57cec5SDimitry Andric
3390b57cec5SDimitry Andrictemplate <size_t _Ip, class... _Types>
3400b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, variant<_Types...>> {
3410b57cec5SDimitry Andric  static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>");
3420b57cec5SDimitry Andric  using type = __type_pack_element<_Ip, _Types...>;
3430b57cec5SDimitry Andric};
3440b57cec5SDimitry Andric
345349cc55cSDimitry Andricinline constexpr size_t variant_npos = static_cast<size_t>(-1);
3460b57cec5SDimitry Andric
347bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI constexpr int __choose_index_type(unsigned int __num_elem) {
348e8d8bef9SDimitry Andric  if (__num_elem < numeric_limits<unsigned char>::max())
3490b57cec5SDimitry Andric    return 0;
350e8d8bef9SDimitry Andric  if (__num_elem < numeric_limits<unsigned short>::max())
3510b57cec5SDimitry Andric    return 1;
3520b57cec5SDimitry Andric  return 2;
3530b57cec5SDimitry Andric}
3540b57cec5SDimitry Andric
3550b57cec5SDimitry Andrictemplate <size_t _NumAlts>
3560b57cec5SDimitry Andricusing __variant_index_t =
3570b57cec5SDimitry Andric#ifndef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
3580b57cec5SDimitry Andric  unsigned int;
3590b57cec5SDimitry Andric#else
3600b57cec5SDimitry Andric  std::tuple_element_t<
3610b57cec5SDimitry Andric      __choose_index_type(_NumAlts),
3620b57cec5SDimitry Andric      std::tuple<unsigned char, unsigned short, unsigned int>
3630b57cec5SDimitry Andric  >;
3640b57cec5SDimitry Andric#endif
3650b57cec5SDimitry Andric
3660b57cec5SDimitry Andrictemplate <class _IndexType>
3670b57cec5SDimitry Andricconstexpr _IndexType __variant_npos = static_cast<_IndexType>(-1);
3680b57cec5SDimitry Andric
369fe6060f1SDimitry Andrictemplate <class... _Types>
370fe6060f1SDimitry Andricclass _LIBCPP_TEMPLATE_VIS variant;
371fe6060f1SDimitry Andric
372fe6060f1SDimitry Andrictemplate <class... _Types>
373fe6060f1SDimitry Andric_LIBCPP_INLINE_VISIBILITY constexpr variant<_Types...>&
374fe6060f1SDimitry Andric__as_variant(variant<_Types...>& __vs) noexcept {
375fe6060f1SDimitry Andric  return __vs;
376fe6060f1SDimitry Andric}
377fe6060f1SDimitry Andric
378fe6060f1SDimitry Andrictemplate <class... _Types>
379fe6060f1SDimitry Andric_LIBCPP_INLINE_VISIBILITY constexpr const variant<_Types...>&
380fe6060f1SDimitry Andric__as_variant(const variant<_Types...>& __vs) noexcept {
381fe6060f1SDimitry Andric  return __vs;
382fe6060f1SDimitry Andric}
383fe6060f1SDimitry Andric
384fe6060f1SDimitry Andrictemplate <class... _Types>
385fe6060f1SDimitry Andric_LIBCPP_INLINE_VISIBILITY constexpr variant<_Types...>&&
386fe6060f1SDimitry Andric__as_variant(variant<_Types...>&& __vs) noexcept {
387fe6060f1SDimitry Andric  return _VSTD::move(__vs);
388fe6060f1SDimitry Andric}
389fe6060f1SDimitry Andric
390fe6060f1SDimitry Andrictemplate <class... _Types>
391fe6060f1SDimitry Andric_LIBCPP_INLINE_VISIBILITY constexpr const variant<_Types...>&&
392fe6060f1SDimitry Andric__as_variant(const variant<_Types...>&& __vs) noexcept {
393fe6060f1SDimitry Andric  return _VSTD::move(__vs);
394fe6060f1SDimitry Andric}
395fe6060f1SDimitry Andric
3960b57cec5SDimitry Andricnamespace __find_detail {
3970b57cec5SDimitry Andric
3980b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
399bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
4000b57cec5SDimitry Andricconstexpr size_t __find_index() {
4010b57cec5SDimitry Andric  constexpr bool __matches[] = {is_same_v<_Tp, _Types>...};
4020b57cec5SDimitry Andric  size_t __result = __not_found;
4030b57cec5SDimitry Andric  for (size_t __i = 0; __i < sizeof...(_Types); ++__i) {
4040b57cec5SDimitry Andric    if (__matches[__i]) {
4050b57cec5SDimitry Andric      if (__result != __not_found) {
4060b57cec5SDimitry Andric        return __ambiguous;
4070b57cec5SDimitry Andric      }
4080b57cec5SDimitry Andric      __result = __i;
4090b57cec5SDimitry Andric    }
4100b57cec5SDimitry Andric  }
4110b57cec5SDimitry Andric  return __result;
4120b57cec5SDimitry Andric}
4130b57cec5SDimitry Andric
4140b57cec5SDimitry Andrictemplate <size_t _Index>
4150b57cec5SDimitry Andricstruct __find_unambiguous_index_sfinae_impl
4160b57cec5SDimitry Andric    : integral_constant<size_t, _Index> {};
4170b57cec5SDimitry Andric
4180b57cec5SDimitry Andrictemplate <>
4190b57cec5SDimitry Andricstruct __find_unambiguous_index_sfinae_impl<__not_found> {};
4200b57cec5SDimitry Andric
4210b57cec5SDimitry Andrictemplate <>
4220b57cec5SDimitry Andricstruct __find_unambiguous_index_sfinae_impl<__ambiguous> {};
4230b57cec5SDimitry Andric
4240b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
4250b57cec5SDimitry Andricstruct __find_unambiguous_index_sfinae
4260b57cec5SDimitry Andric    : __find_unambiguous_index_sfinae_impl<__find_index<_Tp, _Types...>()> {};
4270b57cec5SDimitry Andric
4280b57cec5SDimitry Andric} // namespace __find_detail
4290b57cec5SDimitry Andric
4300b57cec5SDimitry Andricnamespace __variant_detail {
4310b57cec5SDimitry Andric
4320b57cec5SDimitry Andricstruct __valueless_t {};
4330b57cec5SDimitry Andric
4340b57cec5SDimitry Andricenum class _Trait { _TriviallyAvailable, _Available, _Unavailable };
4350b57cec5SDimitry Andric
4360b57cec5SDimitry Andrictemplate <typename _Tp,
4370b57cec5SDimitry Andric          template <typename> class _IsTriviallyAvailable,
4380b57cec5SDimitry Andric          template <typename> class _IsAvailable>
4390b57cec5SDimitry Andricconstexpr _Trait __trait =
4400b57cec5SDimitry Andric    _IsTriviallyAvailable<_Tp>::value
4410b57cec5SDimitry Andric        ? _Trait::_TriviallyAvailable
4420b57cec5SDimitry Andric        : _IsAvailable<_Tp>::value ? _Trait::_Available : _Trait::_Unavailable;
4430b57cec5SDimitry Andric
444bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
4450b57cec5SDimitry Andricconstexpr _Trait __common_trait(initializer_list<_Trait> __traits) {
4460b57cec5SDimitry Andric  _Trait __result = _Trait::_TriviallyAvailable;
4470b57cec5SDimitry Andric  for (_Trait __t : __traits) {
4480b57cec5SDimitry Andric    if (static_cast<int>(__t) > static_cast<int>(__result)) {
4490b57cec5SDimitry Andric      __result = __t;
4500b57cec5SDimitry Andric    }
4510b57cec5SDimitry Andric  }
4520b57cec5SDimitry Andric  return __result;
4530b57cec5SDimitry Andric}
4540b57cec5SDimitry Andric
4550b57cec5SDimitry Andrictemplate <typename... _Types>
4560b57cec5SDimitry Andricstruct __traits {
4570b57cec5SDimitry Andric  static constexpr _Trait __copy_constructible_trait =
458bdd1243dSDimitry Andric      __variant_detail::__common_trait({__trait<_Types,
4590b57cec5SDimitry Andric                              is_trivially_copy_constructible,
4600b57cec5SDimitry Andric                              is_copy_constructible>...});
4610b57cec5SDimitry Andric
4620b57cec5SDimitry Andric  static constexpr _Trait __move_constructible_trait =
463bdd1243dSDimitry Andric      __variant_detail::__common_trait({__trait<_Types,
4640b57cec5SDimitry Andric                              is_trivially_move_constructible,
4650b57cec5SDimitry Andric                              is_move_constructible>...});
4660b57cec5SDimitry Andric
467bdd1243dSDimitry Andric  static constexpr _Trait __copy_assignable_trait = __variant_detail::__common_trait(
4680b57cec5SDimitry Andric      {__copy_constructible_trait,
4690b57cec5SDimitry Andric       __trait<_Types, is_trivially_copy_assignable, is_copy_assignable>...});
4700b57cec5SDimitry Andric
471bdd1243dSDimitry Andric  static constexpr _Trait __move_assignable_trait = __variant_detail::__common_trait(
4720b57cec5SDimitry Andric      {__move_constructible_trait,
4730b57cec5SDimitry Andric       __trait<_Types, is_trivially_move_assignable, is_move_assignable>...});
4740b57cec5SDimitry Andric
475bdd1243dSDimitry Andric  static constexpr _Trait __destructible_trait = __variant_detail::__common_trait(
4760b57cec5SDimitry Andric      {__trait<_Types, is_trivially_destructible, is_destructible>...});
4770b57cec5SDimitry Andric};
4780b57cec5SDimitry Andric
4790b57cec5SDimitry Andricnamespace __access {
4800b57cec5SDimitry Andric
4810b57cec5SDimitry Andricstruct __union {
4820b57cec5SDimitry Andric  template <class _Vp>
483bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
4840b57cec5SDimitry Andric  static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<0>) {
4850b57cec5SDimitry Andric    return _VSTD::forward<_Vp>(__v).__head;
4860b57cec5SDimitry Andric  }
4870b57cec5SDimitry Andric
4880b57cec5SDimitry Andric  template <class _Vp, size_t _Ip>
489bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
4900b57cec5SDimitry Andric  static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<_Ip>) {
4910b57cec5SDimitry Andric    return __get_alt(_VSTD::forward<_Vp>(__v).__tail, in_place_index<_Ip - 1>);
4920b57cec5SDimitry Andric  }
4930b57cec5SDimitry Andric};
4940b57cec5SDimitry Andric
4950b57cec5SDimitry Andricstruct __base {
4960b57cec5SDimitry Andric  template <size_t _Ip, class _Vp>
497bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
4980b57cec5SDimitry Andric  static constexpr auto&& __get_alt(_Vp&& __v) {
4990b57cec5SDimitry Andric    return __union::__get_alt(_VSTD::forward<_Vp>(__v).__data,
5000b57cec5SDimitry Andric                              in_place_index<_Ip>);
5010b57cec5SDimitry Andric  }
5020b57cec5SDimitry Andric};
5030b57cec5SDimitry Andric
5040b57cec5SDimitry Andricstruct __variant {
5050b57cec5SDimitry Andric  template <size_t _Ip, class _Vp>
506bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
5070b57cec5SDimitry Andric  static constexpr auto&& __get_alt(_Vp&& __v) {
508bdd1243dSDimitry Andric    return __base::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v).__impl_);
5090b57cec5SDimitry Andric  }
5100b57cec5SDimitry Andric};
5110b57cec5SDimitry Andric
5120b57cec5SDimitry Andric} // namespace __access
5130b57cec5SDimitry Andric
5140b57cec5SDimitry Andricnamespace __visitation {
5150b57cec5SDimitry Andric
5160b57cec5SDimitry Andricstruct __base {
5170b57cec5SDimitry Andric  template <class _Visitor, class... _Vs>
518bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
5190b57cec5SDimitry Andric  static constexpr decltype(auto)
5200b57cec5SDimitry Andric  __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
5210b57cec5SDimitry Andric    constexpr auto __fdiagonal =
5220b57cec5SDimitry Andric        __make_fdiagonal<_Visitor&&,
5230b57cec5SDimitry Andric                         decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>();
5240b57cec5SDimitry Andric    return __fdiagonal[__index](_VSTD::forward<_Visitor>(__visitor),
5250b57cec5SDimitry Andric                                _VSTD::forward<_Vs>(__vs).__as_base()...);
5260b57cec5SDimitry Andric  }
5270b57cec5SDimitry Andric
5280b57cec5SDimitry Andric  template <class _Visitor, class... _Vs>
529bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
5300b57cec5SDimitry Andric  static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor,
5310b57cec5SDimitry Andric                                              _Vs&&... __vs) {
5320b57cec5SDimitry Andric    constexpr auto __fmatrix =
5330b57cec5SDimitry Andric        __make_fmatrix<_Visitor&&,
5340b57cec5SDimitry Andric                       decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>();
5350b57cec5SDimitry Andric    return __at(__fmatrix, __vs.index()...)(
5360b57cec5SDimitry Andric        _VSTD::forward<_Visitor>(__visitor),
5370b57cec5SDimitry Andric        _VSTD::forward<_Vs>(__vs).__as_base()...);
5380b57cec5SDimitry Andric  }
5390b57cec5SDimitry Andric
5400b57cec5SDimitry Andricprivate:
5410b57cec5SDimitry Andric  template <class _Tp>
542bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
5430b57cec5SDimitry Andric  static constexpr const _Tp& __at(const _Tp& __elem) { return __elem; }
5440b57cec5SDimitry Andric
5450b57cec5SDimitry Andric  template <class _Tp, size_t _Np, typename... _Indices>
546bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
547fe6060f1SDimitry Andric  static constexpr auto&& __at(const __farray<_Tp, _Np>& __elems,
5480b57cec5SDimitry Andric                               size_t __index, _Indices... __indices) {
5490b57cec5SDimitry Andric    return __at(__elems[__index], __indices...);
5500b57cec5SDimitry Andric  }
5510b57cec5SDimitry Andric
5520b57cec5SDimitry Andric  template <class _Fp, class... _Fs>
553*06c3fb27SDimitry Andric  static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_visitor_return_type_check() {
5540b57cec5SDimitry Andric    static_assert(
5550b57cec5SDimitry Andric        __all<is_same_v<_Fp, _Fs>...>::value,
5560b57cec5SDimitry Andric        "`std::visit` requires the visitor to have a single return type.");
5570b57cec5SDimitry Andric  }
5580b57cec5SDimitry Andric
5590b57cec5SDimitry Andric  template <class... _Fs>
560bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
5610b57cec5SDimitry Andric  static constexpr auto __make_farray(_Fs&&... __fs) {
562bdd1243dSDimitry Andric    __std_visit_visitor_return_type_check<__remove_cvref_t<_Fs>...>();
563bdd1243dSDimitry Andric    using __result = __farray<common_type_t<__remove_cvref_t<_Fs>...>, sizeof...(_Fs)>;
5640b57cec5SDimitry Andric    return __result{{_VSTD::forward<_Fs>(__fs)...}};
5650b57cec5SDimitry Andric  }
5660b57cec5SDimitry Andric
567e8d8bef9SDimitry Andric  template <size_t... _Is>
5680b57cec5SDimitry Andric  struct __dispatcher {
5690b57cec5SDimitry Andric    template <class _Fp, class... _Vs>
570bdd1243dSDimitry Andric    _LIBCPP_HIDE_FROM_ABI
5710b57cec5SDimitry Andric    static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) {
57281ad6265SDimitry Andric        return _VSTD::__invoke(
5730b57cec5SDimitry Andric            static_cast<_Fp>(__f),
5740b57cec5SDimitry Andric            __access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...);
5750b57cec5SDimitry Andric    }
5760b57cec5SDimitry Andric  };
5770b57cec5SDimitry Andric
5780b57cec5SDimitry Andric  template <class _Fp, class... _Vs, size_t... _Is>
579bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
5800b57cec5SDimitry Andric  static constexpr auto __make_dispatch(index_sequence<_Is...>) {
5810b57cec5SDimitry Andric    return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>;
5820b57cec5SDimitry Andric  }
5830b57cec5SDimitry Andric
5840b57cec5SDimitry Andric  template <size_t _Ip, class _Fp, class... _Vs>
585bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
5860b57cec5SDimitry Andric  static constexpr auto __make_fdiagonal_impl() {
5870b57cec5SDimitry Andric    return __make_dispatch<_Fp, _Vs...>(
58881ad6265SDimitry Andric        index_sequence<((void)__type_identity<_Vs>{}, _Ip)...>{});
5890b57cec5SDimitry Andric  }
5900b57cec5SDimitry Andric
5910b57cec5SDimitry Andric  template <class _Fp, class... _Vs, size_t... _Is>
592bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
5930b57cec5SDimitry Andric  static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) {
5940b57cec5SDimitry Andric    return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...);
5950b57cec5SDimitry Andric  }
5960b57cec5SDimitry Andric
5970b57cec5SDimitry Andric  template <class _Fp, class _Vp, class... _Vs>
598bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
5990b57cec5SDimitry Andric  static constexpr auto __make_fdiagonal() {
600*06c3fb27SDimitry Andric    constexpr size_t __np = __remove_cvref_t<_Vp>::__size();
601*06c3fb27SDimitry Andric    static_assert(__all<(__np == __remove_cvref_t<_Vs>::__size())...>::value);
602*06c3fb27SDimitry Andric    return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<__np>{});
6030b57cec5SDimitry Andric  }
6040b57cec5SDimitry Andric
6050b57cec5SDimitry Andric  template <class _Fp, class... _Vs, size_t... _Is>
606bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
6070b57cec5SDimitry Andric  static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) {
6080b57cec5SDimitry Andric    return __make_dispatch<_Fp, _Vs...>(__is);
6090b57cec5SDimitry Andric  }
6100b57cec5SDimitry Andric
6110b57cec5SDimitry Andric  template <class _Fp, class... _Vs, size_t... _Is, size_t... _Js, class... _Ls>
612bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
6130b57cec5SDimitry Andric  static constexpr auto __make_fmatrix_impl(index_sequence<_Is...>,
6140b57cec5SDimitry Andric                                            index_sequence<_Js...>,
6150b57cec5SDimitry Andric                                            _Ls... __ls) {
6160b57cec5SDimitry Andric    return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>(
6170b57cec5SDimitry Andric        index_sequence<_Is..., _Js>{}, __ls...)...);
6180b57cec5SDimitry Andric  }
6190b57cec5SDimitry Andric
6200b57cec5SDimitry Andric  template <class _Fp, class... _Vs>
621bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
6220b57cec5SDimitry Andric  static constexpr auto __make_fmatrix() {
6230b57cec5SDimitry Andric    return __make_fmatrix_impl<_Fp, _Vs...>(
624bdd1243dSDimitry Andric        index_sequence<>{}, make_index_sequence<__remove_cvref_t<_Vs>::__size()>{}...);
6250b57cec5SDimitry Andric  }
6260b57cec5SDimitry Andric};
6270b57cec5SDimitry Andric
6280b57cec5SDimitry Andricstruct __variant {
6290b57cec5SDimitry Andric  template <class _Visitor, class... _Vs>
630bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
6310b57cec5SDimitry Andric  static constexpr decltype(auto)
6320b57cec5SDimitry Andric  __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
6330b57cec5SDimitry Andric    return __base::__visit_alt_at(__index,
6340b57cec5SDimitry Andric                                  _VSTD::forward<_Visitor>(__visitor),
635bdd1243dSDimitry Andric                                  _VSTD::forward<_Vs>(__vs).__impl_...);
6360b57cec5SDimitry Andric  }
6370b57cec5SDimitry Andric
6380b57cec5SDimitry Andric  template <class _Visitor, class... _Vs>
639bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
6400b57cec5SDimitry Andric  static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor,
6410b57cec5SDimitry Andric                                              _Vs&&... __vs) {
642fe6060f1SDimitry Andric    return __base::__visit_alt(
643fe6060f1SDimitry Andric        _VSTD::forward<_Visitor>(__visitor),
644bdd1243dSDimitry Andric        _VSTD::__as_variant(_VSTD::forward<_Vs>(__vs)).__impl_...);
6450b57cec5SDimitry Andric  }
6460b57cec5SDimitry Andric
6470b57cec5SDimitry Andric  template <class _Visitor, class... _Vs>
648bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
6490b57cec5SDimitry Andric  static constexpr decltype(auto)
6500b57cec5SDimitry Andric  __visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
6510b57cec5SDimitry Andric    return __visit_alt_at(
6520b57cec5SDimitry Andric        __index,
6530b57cec5SDimitry Andric        __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)),
6540b57cec5SDimitry Andric        _VSTD::forward<_Vs>(__vs)...);
6550b57cec5SDimitry Andric  }
6560b57cec5SDimitry Andric
6570b57cec5SDimitry Andric  template <class _Visitor, class... _Vs>
658bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
6590b57cec5SDimitry Andric  static constexpr decltype(auto) __visit_value(_Visitor&& __visitor,
6600b57cec5SDimitry Andric                                                _Vs&&... __vs) {
6610b57cec5SDimitry Andric    return __visit_alt(
6620b57cec5SDimitry Andric        __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)),
6630b57cec5SDimitry Andric        _VSTD::forward<_Vs>(__vs)...);
6640b57cec5SDimitry Andric  }
665fe6060f1SDimitry Andric
666*06c3fb27SDimitry Andric#if _LIBCPP_STD_VER >= 20
667e8d8bef9SDimitry Andric  template <class _Rp, class _Visitor, class... _Vs>
668bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
669e8d8bef9SDimitry Andric  static constexpr _Rp __visit_value(_Visitor&& __visitor,
670e8d8bef9SDimitry Andric                                     _Vs&&... __vs) {
671e8d8bef9SDimitry Andric    return __visit_alt(
672e8d8bef9SDimitry Andric        __make_value_visitor<_Rp>(_VSTD::forward<_Visitor>(__visitor)),
673e8d8bef9SDimitry Andric        _VSTD::forward<_Vs>(__vs)...);
674e8d8bef9SDimitry Andric  }
675e8d8bef9SDimitry Andric#endif
6760b57cec5SDimitry Andric
6770b57cec5SDimitry Andricprivate:
6780b57cec5SDimitry Andric  template <class _Visitor, class... _Values>
679*06c3fb27SDimitry Andric  static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_exhaustive_visitor_check() {
6800b57cec5SDimitry Andric    static_assert(is_invocable_v<_Visitor, _Values...>,
6810b57cec5SDimitry Andric                  "`std::visit` requires the visitor to be exhaustive.");
6820b57cec5SDimitry Andric  }
6830b57cec5SDimitry Andric
6840b57cec5SDimitry Andric  template <class _Visitor>
6850b57cec5SDimitry Andric  struct __value_visitor {
6860b57cec5SDimitry Andric    template <class... _Alts>
687bdd1243dSDimitry Andric    _LIBCPP_HIDE_FROM_ABI
6880b57cec5SDimitry Andric    constexpr decltype(auto) operator()(_Alts&&... __alts) const {
6890b57cec5SDimitry Andric      __std_visit_exhaustive_visitor_check<
6900b57cec5SDimitry Andric          _Visitor,
6910b57cec5SDimitry Andric          decltype((_VSTD::forward<_Alts>(__alts).__value))...>();
69281ad6265SDimitry Andric      return _VSTD::__invoke(_VSTD::forward<_Visitor>(__visitor),
6930b57cec5SDimitry Andric                             _VSTD::forward<_Alts>(__alts).__value...);
6940b57cec5SDimitry Andric    }
6950b57cec5SDimitry Andric    _Visitor&& __visitor;
6960b57cec5SDimitry Andric  };
6970b57cec5SDimitry Andric
698*06c3fb27SDimitry Andric#if _LIBCPP_STD_VER >= 20
699e8d8bef9SDimitry Andric  template <class _Rp, class _Visitor>
700e8d8bef9SDimitry Andric  struct __value_visitor_return_type {
701e8d8bef9SDimitry Andric    template <class... _Alts>
702bdd1243dSDimitry Andric    _LIBCPP_HIDE_FROM_ABI
703e8d8bef9SDimitry Andric    constexpr _Rp operator()(_Alts&&... __alts) const {
704e8d8bef9SDimitry Andric      __std_visit_exhaustive_visitor_check<
705e8d8bef9SDimitry Andric          _Visitor,
706e8d8bef9SDimitry Andric          decltype((_VSTD::forward<_Alts>(__alts).__value))...>();
707e8d8bef9SDimitry Andric      if constexpr (is_void_v<_Rp>) {
70881ad6265SDimitry Andric        _VSTD::__invoke(_VSTD::forward<_Visitor>(__visitor),
709e8d8bef9SDimitry Andric                        _VSTD::forward<_Alts>(__alts).__value...);
710e8d8bef9SDimitry Andric      }
711e8d8bef9SDimitry Andric      else {
71281ad6265SDimitry Andric        return _VSTD::__invoke(_VSTD::forward<_Visitor>(__visitor),
713e8d8bef9SDimitry Andric                               _VSTD::forward<_Alts>(__alts).__value...);
714e8d8bef9SDimitry Andric      }
715e8d8bef9SDimitry Andric    }
716e8d8bef9SDimitry Andric
717e8d8bef9SDimitry Andric    _Visitor&& __visitor;
718e8d8bef9SDimitry Andric  };
719e8d8bef9SDimitry Andric#endif
720e8d8bef9SDimitry Andric
7210b57cec5SDimitry Andric  template <class _Visitor>
722bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
7230b57cec5SDimitry Andric  static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
7240b57cec5SDimitry Andric    return __value_visitor<_Visitor>{_VSTD::forward<_Visitor>(__visitor)};
7250b57cec5SDimitry Andric  }
726e8d8bef9SDimitry Andric
727*06c3fb27SDimitry Andric#if _LIBCPP_STD_VER >= 20
728e8d8bef9SDimitry Andric  template <class _Rp, class _Visitor>
729bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
730e8d8bef9SDimitry Andric  static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
731e8d8bef9SDimitry Andric    return __value_visitor_return_type<_Rp, _Visitor>{_VSTD::forward<_Visitor>(__visitor)};
732e8d8bef9SDimitry Andric  }
733e8d8bef9SDimitry Andric#endif
7340b57cec5SDimitry Andric};
7350b57cec5SDimitry Andric
7360b57cec5SDimitry Andric} // namespace __visitation
7370b57cec5SDimitry Andric
7380b57cec5SDimitry Andrictemplate <size_t _Index, class _Tp>
7390b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS __alt {
7400b57cec5SDimitry Andric  using __value_type = _Tp;
7410b57cec5SDimitry Andric
7420b57cec5SDimitry Andric  template <class... _Args>
743bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
7440b57cec5SDimitry Andric  explicit constexpr __alt(in_place_t, _Args&&... __args)
7450b57cec5SDimitry Andric      : __value(_VSTD::forward<_Args>(__args)...) {}
7460b57cec5SDimitry Andric
7470b57cec5SDimitry Andric  __value_type __value;
7480b57cec5SDimitry Andric};
7490b57cec5SDimitry Andric
7500b57cec5SDimitry Andrictemplate <_Trait _DestructibleTrait, size_t _Index, class... _Types>
7510b57cec5SDimitry Andricunion _LIBCPP_TEMPLATE_VIS __union;
7520b57cec5SDimitry Andric
7530b57cec5SDimitry Andrictemplate <_Trait _DestructibleTrait, size_t _Index>
7540b57cec5SDimitry Andricunion _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {};
7550b57cec5SDimitry Andric
7560b57cec5SDimitry Andric#define _LIBCPP_VARIANT_UNION(destructible_trait, destructor)                  \
7570b57cec5SDimitry Andric  template <size_t _Index, class _Tp, class... _Types>                         \
7580b57cec5SDimitry Andric  union _LIBCPP_TEMPLATE_VIS __union<destructible_trait,                       \
7590b57cec5SDimitry Andric                                      _Index,                                  \
7600b57cec5SDimitry Andric                                      _Tp,                                     \
7610b57cec5SDimitry Andric                                      _Types...> {                             \
7620b57cec5SDimitry Andric  public:                                                                      \
763bdd1243dSDimitry Andric    _LIBCPP_HIDE_FROM_ABI                                                      \
7640b57cec5SDimitry Andric    explicit constexpr __union(__valueless_t) noexcept : __dummy{} {}          \
7650b57cec5SDimitry Andric                                                                               \
7660b57cec5SDimitry Andric    template <class... _Args>                                                  \
767bdd1243dSDimitry Andric    _LIBCPP_HIDE_FROM_ABI                                                      \
7680b57cec5SDimitry Andric    explicit constexpr __union(in_place_index_t<0>, _Args&&... __args)         \
7690b57cec5SDimitry Andric        : __head(in_place, _VSTD::forward<_Args>(__args)...) {}                \
7700b57cec5SDimitry Andric                                                                               \
7710b57cec5SDimitry Andric    template <size_t _Ip, class... _Args>                                      \
772bdd1243dSDimitry Andric    _LIBCPP_HIDE_FROM_ABI                                                      \
7730b57cec5SDimitry Andric    explicit constexpr __union(in_place_index_t<_Ip>, _Args&&... __args)       \
7740b57cec5SDimitry Andric        : __tail(in_place_index<_Ip - 1>, _VSTD::forward<_Args>(__args)...) {} \
7750b57cec5SDimitry Andric                                                                               \
7760b57cec5SDimitry Andric    __union(const __union&) = default;                                         \
7770b57cec5SDimitry Andric    __union(__union&&) = default;                                              \
7780b57cec5SDimitry Andric                                                                               \
7790b57cec5SDimitry Andric    destructor                                                                 \
7800b57cec5SDimitry Andric                                                                               \
7810b57cec5SDimitry Andric    __union& operator=(const __union&) = default;                              \
7820b57cec5SDimitry Andric    __union& operator=(__union&&) = default;                                   \
7830b57cec5SDimitry Andric                                                                               \
7840b57cec5SDimitry Andric  private:                                                                     \
7850b57cec5SDimitry Andric    char __dummy;                                                              \
7860b57cec5SDimitry Andric    __alt<_Index, _Tp> __head;                                                 \
7870b57cec5SDimitry Andric    __union<destructible_trait, _Index + 1, _Types...> __tail;                 \
7880b57cec5SDimitry Andric                                                                               \
7890b57cec5SDimitry Andric    friend struct __access::__union;                                           \
7900b57cec5SDimitry Andric  }
7910b57cec5SDimitry Andric
7920b57cec5SDimitry Andric_LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable, ~__union() = default;);
7930b57cec5SDimitry Andric_LIBCPP_VARIANT_UNION(_Trait::_Available, ~__union() {});
7940b57cec5SDimitry Andric_LIBCPP_VARIANT_UNION(_Trait::_Unavailable, ~__union() = delete;);
7950b57cec5SDimitry Andric
7960b57cec5SDimitry Andric#undef _LIBCPP_VARIANT_UNION
7970b57cec5SDimitry Andric
7980b57cec5SDimitry Andrictemplate <_Trait _DestructibleTrait, class... _Types>
7990b57cec5SDimitry Andricclass _LIBCPP_TEMPLATE_VIS __base {
8000b57cec5SDimitry Andricpublic:
8010b57cec5SDimitry Andric  using __index_t = __variant_index_t<sizeof...(_Types)>;
8020b57cec5SDimitry Andric
803bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
804753f127fSDimitry Andric  explicit constexpr __base(__valueless_t __tag) noexcept
805753f127fSDimitry Andric      : __data(__tag), __index(__variant_npos<__index_t>) {}
8060b57cec5SDimitry Andric
8070b57cec5SDimitry Andric  template <size_t _Ip, class... _Args>
808bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
8090b57cec5SDimitry Andric  explicit constexpr __base(in_place_index_t<_Ip>, _Args&&... __args)
8100b57cec5SDimitry Andric      :
8110b57cec5SDimitry Andric        __data(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...),
8120b57cec5SDimitry Andric        __index(_Ip) {}
8130b57cec5SDimitry Andric
814bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
8150b57cec5SDimitry Andric  constexpr bool valueless_by_exception() const noexcept {
8160b57cec5SDimitry Andric    return index() == variant_npos;
8170b57cec5SDimitry Andric  }
8180b57cec5SDimitry Andric
819bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
8200b57cec5SDimitry Andric  constexpr size_t index() const noexcept {
8210b57cec5SDimitry Andric    return __index == __variant_npos<__index_t> ? variant_npos : __index;
8220b57cec5SDimitry Andric  }
8230b57cec5SDimitry Andric
8240b57cec5SDimitry Andricprotected:
825bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
8260b57cec5SDimitry Andric  constexpr auto&& __as_base() & { return *this; }
8270b57cec5SDimitry Andric
828bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
8290b57cec5SDimitry Andric  constexpr auto&& __as_base() && { return _VSTD::move(*this); }
8300b57cec5SDimitry Andric
831bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
8320b57cec5SDimitry Andric  constexpr auto&& __as_base() const & { return *this; }
8330b57cec5SDimitry Andric
834bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
8350b57cec5SDimitry Andric  constexpr auto&& __as_base() const && { return _VSTD::move(*this); }
8360b57cec5SDimitry Andric
837bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
8380b57cec5SDimitry Andric  static constexpr size_t __size() { return sizeof...(_Types); }
8390b57cec5SDimitry Andric
8400b57cec5SDimitry Andric  __union<_DestructibleTrait, 0, _Types...> __data;
8410b57cec5SDimitry Andric  __index_t __index;
8420b57cec5SDimitry Andric
8430b57cec5SDimitry Andric  friend struct __access::__base;
8440b57cec5SDimitry Andric  friend struct __visitation::__base;
8450b57cec5SDimitry Andric};
8460b57cec5SDimitry Andric
8470b57cec5SDimitry Andrictemplate <class _Traits, _Trait = _Traits::__destructible_trait>
848e8d8bef9SDimitry Andricclass _LIBCPP_TEMPLATE_VIS __dtor;
8490b57cec5SDimitry Andric
8500b57cec5SDimitry Andric#define _LIBCPP_VARIANT_DESTRUCTOR(destructible_trait, destructor, destroy)    \
8510b57cec5SDimitry Andric  template <class... _Types>                                                   \
852e8d8bef9SDimitry Andric  class _LIBCPP_TEMPLATE_VIS __dtor<__traits<_Types...>,                       \
8530b57cec5SDimitry Andric                                    destructible_trait>                        \
8540b57cec5SDimitry Andric      : public __base<destructible_trait, _Types...> {                         \
8550b57cec5SDimitry Andric    using __base_type = __base<destructible_trait, _Types...>;                 \
8560b57cec5SDimitry Andric    using __index_t = typename __base_type::__index_t;                         \
8570b57cec5SDimitry Andric                                                                               \
8580b57cec5SDimitry Andric  public:                                                                      \
8590b57cec5SDimitry Andric    using __base_type::__base_type;                                            \
8600b57cec5SDimitry Andric    using __base_type::operator=;                                              \
8610b57cec5SDimitry Andric                                                                               \
862e8d8bef9SDimitry Andric    __dtor(const __dtor&) = default;                                           \
863e8d8bef9SDimitry Andric    __dtor(__dtor&&) = default;                                                \
8640b57cec5SDimitry Andric    destructor                                                                 \
865e8d8bef9SDimitry Andric    __dtor& operator=(const __dtor&) = default;                                \
866e8d8bef9SDimitry Andric    __dtor& operator=(__dtor&&) = default;                                     \
8670b57cec5SDimitry Andric                                                                               \
8680b57cec5SDimitry Andric  protected:                                                                   \
869bdd1243dSDimitry Andric    inline _LIBCPP_HIDE_FROM_ABI                                               \
8700b57cec5SDimitry Andric    destroy                                                                    \
8710b57cec5SDimitry Andric  }
8720b57cec5SDimitry Andric
8730b57cec5SDimitry Andric_LIBCPP_VARIANT_DESTRUCTOR(
8740b57cec5SDimitry Andric    _Trait::_TriviallyAvailable,
875e8d8bef9SDimitry Andric    ~__dtor() = default;,
8760b57cec5SDimitry Andric    void __destroy() noexcept { this->__index = __variant_npos<__index_t>; });
8770b57cec5SDimitry Andric
8780b57cec5SDimitry Andric_LIBCPP_VARIANT_DESTRUCTOR(
8790b57cec5SDimitry Andric    _Trait::_Available,
880e8d8bef9SDimitry Andric    ~__dtor() { __destroy(); },
8810b57cec5SDimitry Andric    void __destroy() noexcept {
8820b57cec5SDimitry Andric      if (!this->valueless_by_exception()) {
8830b57cec5SDimitry Andric        __visitation::__base::__visit_alt(
8840b57cec5SDimitry Andric            [](auto& __alt) noexcept {
885bdd1243dSDimitry Andric              using __alt_type = __remove_cvref_t<decltype(__alt)>;
8860b57cec5SDimitry Andric              __alt.~__alt_type();
8870b57cec5SDimitry Andric            },
8880b57cec5SDimitry Andric            *this);
8890b57cec5SDimitry Andric      }
8900b57cec5SDimitry Andric      this->__index = __variant_npos<__index_t>;
8910b57cec5SDimitry Andric    });
8920b57cec5SDimitry Andric
8930b57cec5SDimitry Andric_LIBCPP_VARIANT_DESTRUCTOR(
8940b57cec5SDimitry Andric    _Trait::_Unavailable,
895e8d8bef9SDimitry Andric    ~__dtor() = delete;,
8960b57cec5SDimitry Andric    void __destroy() noexcept = delete;);
8970b57cec5SDimitry Andric
8980b57cec5SDimitry Andric#undef _LIBCPP_VARIANT_DESTRUCTOR
8990b57cec5SDimitry Andric
9000b57cec5SDimitry Andrictemplate <class _Traits>
901e8d8bef9SDimitry Andricclass _LIBCPP_TEMPLATE_VIS __ctor : public __dtor<_Traits> {
902e8d8bef9SDimitry Andric  using __base_type = __dtor<_Traits>;
9030b57cec5SDimitry Andric
9040b57cec5SDimitry Andricpublic:
9050b57cec5SDimitry Andric  using __base_type::__base_type;
9060b57cec5SDimitry Andric  using __base_type::operator=;
9070b57cec5SDimitry Andric
9080b57cec5SDimitry Andricprotected:
9090b57cec5SDimitry Andric  template <size_t _Ip, class _Tp, class... _Args>
910bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
9110b57cec5SDimitry Andric  static _Tp& __construct_alt(__alt<_Ip, _Tp>& __a, _Args&&... __args) {
9120b57cec5SDimitry Andric    ::new ((void*)_VSTD::addressof(__a))
9130b57cec5SDimitry Andric        __alt<_Ip, _Tp>(in_place, _VSTD::forward<_Args>(__args)...);
9140b57cec5SDimitry Andric    return __a.__value;
9150b57cec5SDimitry Andric  }
9160b57cec5SDimitry Andric
9170b57cec5SDimitry Andric  template <class _Rhs>
918bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
919e8d8bef9SDimitry Andric  static void __generic_construct(__ctor& __lhs, _Rhs&& __rhs) {
9200b57cec5SDimitry Andric    __lhs.__destroy();
9210b57cec5SDimitry Andric    if (!__rhs.valueless_by_exception()) {
9220b57cec5SDimitry Andric      __visitation::__base::__visit_alt_at(
9230b57cec5SDimitry Andric          __rhs.index(),
9240b57cec5SDimitry Andric          [](auto& __lhs_alt, auto&& __rhs_alt) {
9250b57cec5SDimitry Andric            __construct_alt(
9260b57cec5SDimitry Andric                __lhs_alt,
9270b57cec5SDimitry Andric                _VSTD::forward<decltype(__rhs_alt)>(__rhs_alt).__value);
9280b57cec5SDimitry Andric          },
9290b57cec5SDimitry Andric          __lhs, _VSTD::forward<_Rhs>(__rhs));
9300b57cec5SDimitry Andric      __lhs.__index = __rhs.index();
9310b57cec5SDimitry Andric    }
9320b57cec5SDimitry Andric  }
9330b57cec5SDimitry Andric};
9340b57cec5SDimitry Andric
9350b57cec5SDimitry Andrictemplate <class _Traits, _Trait = _Traits::__move_constructible_trait>
9360b57cec5SDimitry Andricclass _LIBCPP_TEMPLATE_VIS __move_constructor;
9370b57cec5SDimitry Andric
9380b57cec5SDimitry Andric#define _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait,             \
9390b57cec5SDimitry Andric                                         move_constructor)                     \
9400b57cec5SDimitry Andric  template <class... _Types>                                                   \
9410b57cec5SDimitry Andric  class _LIBCPP_TEMPLATE_VIS __move_constructor<__traits<_Types...>,           \
9420b57cec5SDimitry Andric                                                move_constructible_trait>      \
943e8d8bef9SDimitry Andric      : public __ctor<__traits<_Types...>> {                                   \
944e8d8bef9SDimitry Andric    using __base_type = __ctor<__traits<_Types...>>;                           \
9450b57cec5SDimitry Andric                                                                               \
9460b57cec5SDimitry Andric  public:                                                                      \
9470b57cec5SDimitry Andric    using __base_type::__base_type;                                            \
9480b57cec5SDimitry Andric    using __base_type::operator=;                                              \
9490b57cec5SDimitry Andric                                                                               \
9500b57cec5SDimitry Andric    __move_constructor(const __move_constructor&) = default;                   \
9510b57cec5SDimitry Andric    move_constructor                                                           \
9520b57cec5SDimitry Andric    ~__move_constructor() = default;                                           \
9530b57cec5SDimitry Andric    __move_constructor& operator=(const __move_constructor&) = default;        \
9540b57cec5SDimitry Andric    __move_constructor& operator=(__move_constructor&&) = default;             \
9550b57cec5SDimitry Andric  }
9560b57cec5SDimitry Andric
9570b57cec5SDimitry Andric_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
9580b57cec5SDimitry Andric    _Trait::_TriviallyAvailable,
9590b57cec5SDimitry Andric    __move_constructor(__move_constructor&& __that) = default;);
9600b57cec5SDimitry Andric
9610b57cec5SDimitry Andric_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
9620b57cec5SDimitry Andric    _Trait::_Available,
9630b57cec5SDimitry Andric    __move_constructor(__move_constructor&& __that) noexcept(
9640b57cec5SDimitry Andric        __all<is_nothrow_move_constructible_v<_Types>...>::value)
9650b57cec5SDimitry Andric        : __move_constructor(__valueless_t{}) {
9660b57cec5SDimitry Andric      this->__generic_construct(*this, _VSTD::move(__that));
9670b57cec5SDimitry Andric    });
9680b57cec5SDimitry Andric
9690b57cec5SDimitry Andric_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
9700b57cec5SDimitry Andric    _Trait::_Unavailable,
9710b57cec5SDimitry Andric    __move_constructor(__move_constructor&&) = delete;);
9720b57cec5SDimitry Andric
9730b57cec5SDimitry Andric#undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR
9740b57cec5SDimitry Andric
9750b57cec5SDimitry Andrictemplate <class _Traits, _Trait = _Traits::__copy_constructible_trait>
9760b57cec5SDimitry Andricclass _LIBCPP_TEMPLATE_VIS __copy_constructor;
9770b57cec5SDimitry Andric
9780b57cec5SDimitry Andric#define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait,             \
9790b57cec5SDimitry Andric                                         copy_constructor)                     \
9800b57cec5SDimitry Andric  template <class... _Types>                                                   \
9810b57cec5SDimitry Andric  class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>,           \
9820b57cec5SDimitry Andric                                                 copy_constructible_trait>     \
9830b57cec5SDimitry Andric      : public __move_constructor<__traits<_Types...>> {                       \
9840b57cec5SDimitry Andric    using __base_type = __move_constructor<__traits<_Types...>>;               \
9850b57cec5SDimitry Andric                                                                               \
9860b57cec5SDimitry Andric  public:                                                                      \
9870b57cec5SDimitry Andric    using __base_type::__base_type;                                            \
9880b57cec5SDimitry Andric    using __base_type::operator=;                                              \
9890b57cec5SDimitry Andric                                                                               \
9900b57cec5SDimitry Andric    copy_constructor                                                           \
9910b57cec5SDimitry Andric    __copy_constructor(__copy_constructor&&) = default;                        \
9920b57cec5SDimitry Andric    ~__copy_constructor() = default;                                           \
9930b57cec5SDimitry Andric    __copy_constructor& operator=(const __copy_constructor&) = default;        \
9940b57cec5SDimitry Andric    __copy_constructor& operator=(__copy_constructor&&) = default;             \
9950b57cec5SDimitry Andric  }
9960b57cec5SDimitry Andric
9970b57cec5SDimitry Andric_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
9980b57cec5SDimitry Andric    _Trait::_TriviallyAvailable,
9990b57cec5SDimitry Andric    __copy_constructor(const __copy_constructor& __that) = default;);
10000b57cec5SDimitry Andric
10010b57cec5SDimitry Andric_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
10020b57cec5SDimitry Andric    _Trait::_Available,
10030b57cec5SDimitry Andric    __copy_constructor(const __copy_constructor& __that)
10040b57cec5SDimitry Andric        : __copy_constructor(__valueless_t{}) {
10050b57cec5SDimitry Andric      this->__generic_construct(*this, __that);
10060b57cec5SDimitry Andric    });
10070b57cec5SDimitry Andric
10080b57cec5SDimitry Andric_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
10090b57cec5SDimitry Andric    _Trait::_Unavailable,
10100b57cec5SDimitry Andric    __copy_constructor(const __copy_constructor&) = delete;);
10110b57cec5SDimitry Andric
10120b57cec5SDimitry Andric#undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR
10130b57cec5SDimitry Andric
10140b57cec5SDimitry Andrictemplate <class _Traits>
10150b57cec5SDimitry Andricclass _LIBCPP_TEMPLATE_VIS __assignment : public __copy_constructor<_Traits> {
10160b57cec5SDimitry Andric  using __base_type = __copy_constructor<_Traits>;
10170b57cec5SDimitry Andric
10180b57cec5SDimitry Andricpublic:
10190b57cec5SDimitry Andric  using __base_type::__base_type;
10200b57cec5SDimitry Andric  using __base_type::operator=;
10210b57cec5SDimitry Andric
10220b57cec5SDimitry Andric  template <size_t _Ip, class... _Args>
1023bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
10240b57cec5SDimitry Andric  auto& __emplace(_Args&&... __args) {
10250b57cec5SDimitry Andric    this->__destroy();
10260b57cec5SDimitry Andric    auto& __res = this->__construct_alt(__access::__base::__get_alt<_Ip>(*this),
10270b57cec5SDimitry Andric                          _VSTD::forward<_Args>(__args)...);
10280b57cec5SDimitry Andric    this->__index = _Ip;
10290b57cec5SDimitry Andric    return __res;
10300b57cec5SDimitry Andric  }
10310b57cec5SDimitry Andric
10320b57cec5SDimitry Andricprotected:
10330b57cec5SDimitry Andric  template <size_t _Ip, class _Tp, class _Arg>
1034bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
10350b57cec5SDimitry Andric  void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) {
10360b57cec5SDimitry Andric    if (this->index() == _Ip) {
10370b57cec5SDimitry Andric      __a.__value = _VSTD::forward<_Arg>(__arg);
10380b57cec5SDimitry Andric    } else {
10390b57cec5SDimitry Andric      struct {
1040*06c3fb27SDimitry Andric        _LIBCPP_HIDE_FROM_ABI void operator()(true_type) const {
10410b57cec5SDimitry Andric          __this->__emplace<_Ip>(_VSTD::forward<_Arg>(__arg));
10420b57cec5SDimitry Andric        }
1043*06c3fb27SDimitry Andric        _LIBCPP_HIDE_FROM_ABI void operator()(false_type) const {
10440b57cec5SDimitry Andric          __this->__emplace<_Ip>(_Tp(_VSTD::forward<_Arg>(__arg)));
10450b57cec5SDimitry Andric        }
10460b57cec5SDimitry Andric        __assignment* __this;
10470b57cec5SDimitry Andric        _Arg&& __arg;
10480b57cec5SDimitry Andric      } __impl{this, _VSTD::forward<_Arg>(__arg)};
10490b57cec5SDimitry Andric      __impl(bool_constant<is_nothrow_constructible_v<_Tp, _Arg> ||
10500b57cec5SDimitry Andric                           !is_nothrow_move_constructible_v<_Tp>>{});
10510b57cec5SDimitry Andric    }
10520b57cec5SDimitry Andric  }
10530b57cec5SDimitry Andric
10540b57cec5SDimitry Andric  template <class _That>
1055bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
10560b57cec5SDimitry Andric  void __generic_assign(_That&& __that) {
10570b57cec5SDimitry Andric    if (this->valueless_by_exception() && __that.valueless_by_exception()) {
10580b57cec5SDimitry Andric      // do nothing.
10590b57cec5SDimitry Andric    } else if (__that.valueless_by_exception()) {
10600b57cec5SDimitry Andric      this->__destroy();
10610b57cec5SDimitry Andric    } else {
10620b57cec5SDimitry Andric      __visitation::__base::__visit_alt_at(
10630b57cec5SDimitry Andric          __that.index(),
10640b57cec5SDimitry Andric          [this](auto& __this_alt, auto&& __that_alt) {
10650b57cec5SDimitry Andric            this->__assign_alt(
10660b57cec5SDimitry Andric                __this_alt,
10670b57cec5SDimitry Andric                _VSTD::forward<decltype(__that_alt)>(__that_alt).__value);
10680b57cec5SDimitry Andric          },
10690b57cec5SDimitry Andric          *this, _VSTD::forward<_That>(__that));
10700b57cec5SDimitry Andric    }
10710b57cec5SDimitry Andric  }
10720b57cec5SDimitry Andric};
10730b57cec5SDimitry Andric
10740b57cec5SDimitry Andrictemplate <class _Traits, _Trait = _Traits::__move_assignable_trait>
10750b57cec5SDimitry Andricclass _LIBCPP_TEMPLATE_VIS __move_assignment;
10760b57cec5SDimitry Andric
10770b57cec5SDimitry Andric#define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait,                 \
10780b57cec5SDimitry Andric                                        move_assignment)                       \
10790b57cec5SDimitry Andric  template <class... _Types>                                                   \
10800b57cec5SDimitry Andric  class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>,            \
10810b57cec5SDimitry Andric                                                move_assignable_trait>         \
10820b57cec5SDimitry Andric      : public __assignment<__traits<_Types...>> {                             \
10830b57cec5SDimitry Andric    using __base_type = __assignment<__traits<_Types...>>;                     \
10840b57cec5SDimitry Andric                                                                               \
10850b57cec5SDimitry Andric  public:                                                                      \
10860b57cec5SDimitry Andric    using __base_type::__base_type;                                            \
10870b57cec5SDimitry Andric    using __base_type::operator=;                                              \
10880b57cec5SDimitry Andric                                                                               \
10890b57cec5SDimitry Andric    __move_assignment(const __move_assignment&) = default;                     \
10900b57cec5SDimitry Andric    __move_assignment(__move_assignment&&) = default;                          \
10910b57cec5SDimitry Andric    ~__move_assignment() = default;                                            \
10920b57cec5SDimitry Andric    __move_assignment& operator=(const __move_assignment&) = default;          \
10930b57cec5SDimitry Andric    move_assignment                                                            \
10940b57cec5SDimitry Andric  }
10950b57cec5SDimitry Andric
10960b57cec5SDimitry Andric_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
10970b57cec5SDimitry Andric    _Trait::_TriviallyAvailable,
10980b57cec5SDimitry Andric    __move_assignment& operator=(__move_assignment&& __that) = default;);
10990b57cec5SDimitry Andric
11000b57cec5SDimitry Andric_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
11010b57cec5SDimitry Andric    _Trait::_Available,
11020b57cec5SDimitry Andric    __move_assignment& operator=(__move_assignment&& __that) noexcept(
11030b57cec5SDimitry Andric        __all<(is_nothrow_move_constructible_v<_Types> &&
11040b57cec5SDimitry Andric               is_nothrow_move_assignable_v<_Types>)...>::value) {
11050b57cec5SDimitry Andric      this->__generic_assign(_VSTD::move(__that));
11060b57cec5SDimitry Andric      return *this;
11070b57cec5SDimitry Andric    });
11080b57cec5SDimitry Andric
11090b57cec5SDimitry Andric_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
11100b57cec5SDimitry Andric    _Trait::_Unavailable,
11110b57cec5SDimitry Andric    __move_assignment& operator=(__move_assignment&&) = delete;);
11120b57cec5SDimitry Andric
11130b57cec5SDimitry Andric#undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT
11140b57cec5SDimitry Andric
11150b57cec5SDimitry Andrictemplate <class _Traits, _Trait = _Traits::__copy_assignable_trait>
11160b57cec5SDimitry Andricclass _LIBCPP_TEMPLATE_VIS __copy_assignment;
11170b57cec5SDimitry Andric
11180b57cec5SDimitry Andric#define _LIBCPP_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait,                 \
11190b57cec5SDimitry Andric                                        copy_assignment)                       \
11200b57cec5SDimitry Andric  template <class... _Types>                                                   \
11210b57cec5SDimitry Andric  class _LIBCPP_TEMPLATE_VIS __copy_assignment<__traits<_Types...>,            \
11220b57cec5SDimitry Andric                                                copy_assignable_trait>         \
11230b57cec5SDimitry Andric      : public __move_assignment<__traits<_Types...>> {                        \
11240b57cec5SDimitry Andric    using __base_type = __move_assignment<__traits<_Types...>>;                \
11250b57cec5SDimitry Andric                                                                               \
11260b57cec5SDimitry Andric  public:                                                                      \
11270b57cec5SDimitry Andric    using __base_type::__base_type;                                            \
11280b57cec5SDimitry Andric    using __base_type::operator=;                                              \
11290b57cec5SDimitry Andric                                                                               \
11300b57cec5SDimitry Andric    __copy_assignment(const __copy_assignment&) = default;                     \
11310b57cec5SDimitry Andric    __copy_assignment(__copy_assignment&&) = default;                          \
11320b57cec5SDimitry Andric    ~__copy_assignment() = default;                                            \
11330b57cec5SDimitry Andric    copy_assignment                                                            \
11340b57cec5SDimitry Andric    __copy_assignment& operator=(__copy_assignment&&) = default;               \
11350b57cec5SDimitry Andric  }
11360b57cec5SDimitry Andric
11370b57cec5SDimitry Andric_LIBCPP_VARIANT_COPY_ASSIGNMENT(
11380b57cec5SDimitry Andric    _Trait::_TriviallyAvailable,
11390b57cec5SDimitry Andric    __copy_assignment& operator=(const __copy_assignment& __that) = default;);
11400b57cec5SDimitry Andric
11410b57cec5SDimitry Andric_LIBCPP_VARIANT_COPY_ASSIGNMENT(
11420b57cec5SDimitry Andric    _Trait::_Available,
11430b57cec5SDimitry Andric    __copy_assignment& operator=(const __copy_assignment& __that) {
11440b57cec5SDimitry Andric      this->__generic_assign(__that);
11450b57cec5SDimitry Andric      return *this;
11460b57cec5SDimitry Andric    });
11470b57cec5SDimitry Andric
11480b57cec5SDimitry Andric_LIBCPP_VARIANT_COPY_ASSIGNMENT(
11490b57cec5SDimitry Andric    _Trait::_Unavailable,
11500b57cec5SDimitry Andric    __copy_assignment& operator=(const __copy_assignment&) = delete;);
11510b57cec5SDimitry Andric
11520b57cec5SDimitry Andric#undef _LIBCPP_VARIANT_COPY_ASSIGNMENT
11530b57cec5SDimitry Andric
11540b57cec5SDimitry Andrictemplate <class... _Types>
11550b57cec5SDimitry Andricclass _LIBCPP_TEMPLATE_VIS __impl
11560b57cec5SDimitry Andric    : public __copy_assignment<__traits<_Types...>> {
11570b57cec5SDimitry Andric  using __base_type = __copy_assignment<__traits<_Types...>>;
11580b57cec5SDimitry Andric
11590b57cec5SDimitry Andricpublic:
116081ad6265SDimitry Andric  using __base_type::__base_type; // get in_place_index_t constructor & friends
1161*06c3fb27SDimitry Andric  _LIBCPP_HIDE_FROM_ABI __impl(__impl const&) = default;
1162*06c3fb27SDimitry Andric  _LIBCPP_HIDE_FROM_ABI __impl(__impl&&) = default;
1163*06c3fb27SDimitry Andric  _LIBCPP_HIDE_FROM_ABI __impl& operator=(__impl const&) = default;
1164*06c3fb27SDimitry Andric  _LIBCPP_HIDE_FROM_ABI __impl& operator=(__impl&&) = default;
11650b57cec5SDimitry Andric
11660b57cec5SDimitry Andric  template <size_t _Ip, class _Arg>
1167bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
11680b57cec5SDimitry Andric  void __assign(_Arg&& __arg) {
11690b57cec5SDimitry Andric    this->__assign_alt(__access::__base::__get_alt<_Ip>(*this),
11700b57cec5SDimitry Andric                       _VSTD::forward<_Arg>(__arg));
11710b57cec5SDimitry Andric  }
11720b57cec5SDimitry Andric
1173bdd1243dSDimitry Andric  inline _LIBCPP_HIDE_FROM_ABI
11740b57cec5SDimitry Andric  void __swap(__impl& __that)  {
11750b57cec5SDimitry Andric    if (this->valueless_by_exception() && __that.valueless_by_exception()) {
11760b57cec5SDimitry Andric      // do nothing.
11770b57cec5SDimitry Andric    } else if (this->index() == __that.index()) {
11780b57cec5SDimitry Andric      __visitation::__base::__visit_alt_at(
11790b57cec5SDimitry Andric          this->index(),
11800b57cec5SDimitry Andric          [](auto& __this_alt, auto& __that_alt) {
11810b57cec5SDimitry Andric            using _VSTD::swap;
11820b57cec5SDimitry Andric            swap(__this_alt.__value, __that_alt.__value);
11830b57cec5SDimitry Andric          },
11840b57cec5SDimitry Andric          *this,
11850b57cec5SDimitry Andric          __that);
11860b57cec5SDimitry Andric    } else {
11870b57cec5SDimitry Andric      __impl* __lhs = this;
11880b57cec5SDimitry Andric      __impl* __rhs = _VSTD::addressof(__that);
11890b57cec5SDimitry Andric      if (__lhs->__move_nothrow() && !__rhs->__move_nothrow()) {
11900b57cec5SDimitry Andric        _VSTD::swap(__lhs, __rhs);
11910b57cec5SDimitry Andric      }
11920b57cec5SDimitry Andric      __impl __tmp(_VSTD::move(*__rhs));
1193*06c3fb27SDimitry Andric#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
11945ffd83dbSDimitry Andric      if constexpr (__all<is_nothrow_move_constructible_v<_Types>...>::value) {
11955ffd83dbSDimitry Andric        this->__generic_construct(*__rhs, _VSTD::move(*__lhs));
11965ffd83dbSDimitry Andric      } else {
11970b57cec5SDimitry Andric        // EXTENSION: When the move construction of `__lhs` into `__rhs` throws
11980b57cec5SDimitry Andric        // and `__tmp` is nothrow move constructible then we move `__tmp` back
11990b57cec5SDimitry Andric        // into `__rhs` and provide the strong exception safety guarantee.
12000b57cec5SDimitry Andric        try {
12010b57cec5SDimitry Andric          this->__generic_construct(*__rhs, _VSTD::move(*__lhs));
12020b57cec5SDimitry Andric        } catch (...) {
12030b57cec5SDimitry Andric          if (__tmp.__move_nothrow()) {
12040b57cec5SDimitry Andric            this->__generic_construct(*__rhs, _VSTD::move(__tmp));
12050b57cec5SDimitry Andric          }
12060b57cec5SDimitry Andric          throw;
12070b57cec5SDimitry Andric        }
12085ffd83dbSDimitry Andric      }
12090b57cec5SDimitry Andric#else
12105ffd83dbSDimitry Andric      // this isn't consolidated with the `if constexpr` branch above due to
12115ffd83dbSDimitry Andric      // `throw` being ill-formed with exceptions disabled even when discarded.
12120b57cec5SDimitry Andric      this->__generic_construct(*__rhs, _VSTD::move(*__lhs));
12130b57cec5SDimitry Andric#endif
12140b57cec5SDimitry Andric      this->__generic_construct(*__lhs, _VSTD::move(__tmp));
12150b57cec5SDimitry Andric    }
12160b57cec5SDimitry Andric  }
12170b57cec5SDimitry Andric
12180b57cec5SDimitry Andricprivate:
1219bdd1243dSDimitry Andric  inline _LIBCPP_HIDE_FROM_ABI
12200b57cec5SDimitry Andric  bool __move_nothrow() const {
12210b57cec5SDimitry Andric    constexpr bool __results[] = {is_nothrow_move_constructible_v<_Types>...};
12220b57cec5SDimitry Andric    return this->valueless_by_exception() || __results[this->index()];
12230b57cec5SDimitry Andric  }
12240b57cec5SDimitry Andric};
12250b57cec5SDimitry Andric
12260b57cec5SDimitry Andricstruct __no_narrowing_check {
12270b57cec5SDimitry Andric  template <class _Dest, class _Source>
122881ad6265SDimitry Andric  using _Apply = __type_identity<_Dest>;
12290b57cec5SDimitry Andric};
12300b57cec5SDimitry Andric
12310b57cec5SDimitry Andricstruct __narrowing_check {
12320b57cec5SDimitry Andric  template <class _Dest>
123381ad6265SDimitry Andric  static auto __test_impl(_Dest (&&)[1]) -> __type_identity<_Dest>;
12340b57cec5SDimitry Andric  template <class _Dest, class _Source>
1235bdd1243dSDimitry Andric  using _Apply _LIBCPP_NODEBUG = decltype(__test_impl<_Dest>({std::declval<_Source>()}));
12360b57cec5SDimitry Andric};
12370b57cec5SDimitry Andric
12380b57cec5SDimitry Andrictemplate <class _Dest, class _Source>
1239349cc55cSDimitry Andricusing __check_for_narrowing _LIBCPP_NODEBUG =
12400b57cec5SDimitry Andric  typename _If<
12410b57cec5SDimitry Andric#ifdef _LIBCPP_ENABLE_NARROWING_CONVERSIONS_IN_VARIANT
12420b57cec5SDimitry Andric    false &&
12430b57cec5SDimitry Andric#endif
12440b57cec5SDimitry Andric    is_arithmetic<_Dest>::value,
12450b57cec5SDimitry Andric    __narrowing_check,
12460b57cec5SDimitry Andric    __no_narrowing_check
12470b57cec5SDimitry Andric  >::template _Apply<_Dest, _Source>;
12480b57cec5SDimitry Andric
12490b57cec5SDimitry Andrictemplate <class _Tp, size_t _Idx>
12500b57cec5SDimitry Andricstruct __overload {
12510b57cec5SDimitry Andric  template <class _Up>
12520b57cec5SDimitry Andric  auto operator()(_Tp, _Up&&) const -> __check_for_narrowing<_Tp, _Up>;
12530b57cec5SDimitry Andric};
12540b57cec5SDimitry Andric
12550b57cec5SDimitry Andrictemplate <class _Tp, size_t>
12560b57cec5SDimitry Andricstruct __overload_bool  {
1257bdd1243dSDimitry Andric  template <class _Up, class _Ap = __remove_cvref_t<_Up>>
12580b57cec5SDimitry Andric  auto operator()(bool, _Up&&) const
125981ad6265SDimitry Andric      -> enable_if_t<is_same_v<_Ap, bool>, __type_identity<_Tp>>;
12600b57cec5SDimitry Andric};
12610b57cec5SDimitry Andric
12620b57cec5SDimitry Andrictemplate <size_t _Idx>
12630b57cec5SDimitry Andricstruct __overload<bool, _Idx> : __overload_bool<bool, _Idx> {};
12640b57cec5SDimitry Andrictemplate <size_t _Idx>
12650b57cec5SDimitry Andricstruct __overload<bool const, _Idx> : __overload_bool<bool const, _Idx> {};
12660b57cec5SDimitry Andrictemplate <size_t _Idx>
12670b57cec5SDimitry Andricstruct __overload<bool volatile, _Idx> : __overload_bool<bool volatile, _Idx> {};
12680b57cec5SDimitry Andrictemplate <size_t _Idx>
12690b57cec5SDimitry Andricstruct __overload<bool const volatile, _Idx> : __overload_bool<bool const volatile, _Idx> {};
12700b57cec5SDimitry Andric
12710b57cec5SDimitry Andrictemplate <class ..._Bases>
12720b57cec5SDimitry Andricstruct __all_overloads : _Bases... {
12730b57cec5SDimitry Andric  void operator()() const;
12740b57cec5SDimitry Andric  using _Bases::operator()...;
12750b57cec5SDimitry Andric};
12760b57cec5SDimitry Andric
1277*06c3fb27SDimitry Andrictemplate <class _IdxSeq>
12780b57cec5SDimitry Andricstruct __make_overloads_imp;
12790b57cec5SDimitry Andric
12800b57cec5SDimitry Andrictemplate <size_t ..._Idx>
12810b57cec5SDimitry Andricstruct __make_overloads_imp<__tuple_indices<_Idx...> > {
12820b57cec5SDimitry Andric  template <class ..._Types>
1283349cc55cSDimitry Andric  using _Apply _LIBCPP_NODEBUG = __all_overloads<__overload<_Types, _Idx>...>;
12840b57cec5SDimitry Andric};
12850b57cec5SDimitry Andric
12860b57cec5SDimitry Andrictemplate <class ..._Types>
1287349cc55cSDimitry Andricusing _MakeOverloads _LIBCPP_NODEBUG = typename __make_overloads_imp<
12880b57cec5SDimitry Andric    __make_indices_imp<sizeof...(_Types), 0> >::template _Apply<_Types...>;
12890b57cec5SDimitry Andric
12900b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
12910b57cec5SDimitry Andricusing __best_match_t =
12920b57cec5SDimitry Andric    typename invoke_result_t<_MakeOverloads<_Types...>, _Tp, _Tp>::type;
12930b57cec5SDimitry Andric
12941fd87a68SDimitry Andric} // namespace __variant_detail
12950b57cec5SDimitry Andric
12960b57cec5SDimitry Andrictemplate <class... _Types>
1297*06c3fb27SDimitry Andricclass _LIBCPP_TEMPLATE_VIS _LIBCPP_DECLSPEC_EMPTY_BASES variant
12980b57cec5SDimitry Andric    : private __sfinae_ctor_base<
12990b57cec5SDimitry Andric          __all<is_copy_constructible_v<_Types>...>::value,
13000b57cec5SDimitry Andric          __all<is_move_constructible_v<_Types>...>::value>,
13010b57cec5SDimitry Andric      private __sfinae_assign_base<
13020b57cec5SDimitry Andric          __all<(is_copy_constructible_v<_Types> &&
13030b57cec5SDimitry Andric                 is_copy_assignable_v<_Types>)...>::value,
13040b57cec5SDimitry Andric          __all<(is_move_constructible_v<_Types> &&
13050b57cec5SDimitry Andric                 is_move_assignable_v<_Types>)...>::value> {
13060b57cec5SDimitry Andric  static_assert(0 < sizeof...(_Types),
13070b57cec5SDimitry Andric                "variant must consist of at least one alternative.");
13080b57cec5SDimitry Andric
13090b57cec5SDimitry Andric  static_assert(__all<!is_array_v<_Types>...>::value,
13100b57cec5SDimitry Andric                "variant can not have an array type as an alternative.");
13110b57cec5SDimitry Andric
13120b57cec5SDimitry Andric  static_assert(__all<!is_reference_v<_Types>...>::value,
13130b57cec5SDimitry Andric                "variant can not have a reference type as an alternative.");
13140b57cec5SDimitry Andric
13150b57cec5SDimitry Andric  static_assert(__all<!is_void_v<_Types>...>::value,
13160b57cec5SDimitry Andric                "variant can not have a void type as an alternative.");
13170b57cec5SDimitry Andric
13180b57cec5SDimitry Andric  using __first_type = variant_alternative_t<0, variant>;
13190b57cec5SDimitry Andric
13200b57cec5SDimitry Andricpublic:
13210b57cec5SDimitry Andric  template <bool _Dummy = true,
13220b57cec5SDimitry Andric            enable_if_t<__dependent_type<is_default_constructible<__first_type>,
13230b57cec5SDimitry Andric                                         _Dummy>::value,
13240b57cec5SDimitry Andric                        int> = 0>
1325bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
13260b57cec5SDimitry Andric  constexpr variant() noexcept(is_nothrow_default_constructible_v<__first_type>)
1327bdd1243dSDimitry Andric      : __impl_(in_place_index<0>) {}
13280b57cec5SDimitry Andric
1329*06c3fb27SDimitry Andric  _LIBCPP_HIDE_FROM_ABI constexpr variant(const variant&) = default;
1330*06c3fb27SDimitry Andric  _LIBCPP_HIDE_FROM_ABI constexpr variant(variant&&) = default;
13310b57cec5SDimitry Andric
13320b57cec5SDimitry Andric  template <
13330b57cec5SDimitry Andric      class _Arg,
1334bdd1243dSDimitry Andric      enable_if_t<!is_same_v<__remove_cvref_t<_Arg>, variant>, int> = 0,
1335bdd1243dSDimitry Andric      enable_if_t<!__is_inplace_type<__remove_cvref_t<_Arg>>::value, int> = 0,
1336bdd1243dSDimitry Andric      enable_if_t<!__is_inplace_index<__remove_cvref_t<_Arg>>::value, int> = 0,
13370b57cec5SDimitry Andric      class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,
13380b57cec5SDimitry Andric      size_t _Ip =
13390b57cec5SDimitry Andric          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
13400b57cec5SDimitry Andric      enable_if_t<is_constructible_v<_Tp, _Arg>, int> = 0>
1341bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
13420b57cec5SDimitry Andric  constexpr variant(_Arg&& __arg) noexcept(
13430b57cec5SDimitry Andric      is_nothrow_constructible_v<_Tp, _Arg>)
1344bdd1243dSDimitry Andric      : __impl_(in_place_index<_Ip>, _VSTD::forward<_Arg>(__arg)) {}
13450b57cec5SDimitry Andric
13460b57cec5SDimitry Andric  template <size_t _Ip, class... _Args,
13470b57cec5SDimitry Andric            class = enable_if_t<(_Ip < sizeof...(_Types)), int>,
13480b57cec5SDimitry Andric            class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
13490b57cec5SDimitry Andric            enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
1350bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
13510b57cec5SDimitry Andric  explicit constexpr variant(
13520b57cec5SDimitry Andric      in_place_index_t<_Ip>,
13530b57cec5SDimitry Andric      _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
1354bdd1243dSDimitry Andric      : __impl_(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
13550b57cec5SDimitry Andric
13560b57cec5SDimitry Andric  template <
13570b57cec5SDimitry Andric      size_t _Ip,
13580b57cec5SDimitry Andric      class _Up,
13590b57cec5SDimitry Andric      class... _Args,
13600b57cec5SDimitry Andric      enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
13610b57cec5SDimitry Andric      class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
13620b57cec5SDimitry Andric      enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
13630b57cec5SDimitry Andric                  int> = 0>
1364bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
13650b57cec5SDimitry Andric  explicit constexpr variant(
13660b57cec5SDimitry Andric      in_place_index_t<_Ip>,
13670b57cec5SDimitry Andric      initializer_list<_Up> __il,
13680b57cec5SDimitry Andric      _Args&&... __args) noexcept(
13690b57cec5SDimitry Andric      is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>)
1370bdd1243dSDimitry Andric      : __impl_(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
13710b57cec5SDimitry Andric
13720b57cec5SDimitry Andric  template <
13730b57cec5SDimitry Andric      class _Tp,
13740b57cec5SDimitry Andric      class... _Args,
13750b57cec5SDimitry Andric      size_t _Ip =
13760b57cec5SDimitry Andric          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
13770b57cec5SDimitry Andric      enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
1378bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
13790b57cec5SDimitry Andric  explicit constexpr variant(in_place_type_t<_Tp>, _Args&&... __args) noexcept(
13800b57cec5SDimitry Andric      is_nothrow_constructible_v<_Tp, _Args...>)
1381bdd1243dSDimitry Andric      : __impl_(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
13820b57cec5SDimitry Andric
13830b57cec5SDimitry Andric  template <
13840b57cec5SDimitry Andric      class _Tp,
13850b57cec5SDimitry Andric      class _Up,
13860b57cec5SDimitry Andric      class... _Args,
13870b57cec5SDimitry Andric      size_t _Ip =
13880b57cec5SDimitry Andric          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
13890b57cec5SDimitry Andric      enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
13900b57cec5SDimitry Andric                  int> = 0>
1391bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
13920b57cec5SDimitry Andric  explicit constexpr variant(
13930b57cec5SDimitry Andric      in_place_type_t<_Tp>,
13940b57cec5SDimitry Andric      initializer_list<_Up> __il,
13950b57cec5SDimitry Andric      _Args&&... __args) noexcept(
13960b57cec5SDimitry Andric      is_nothrow_constructible_v<_Tp, initializer_list< _Up>&, _Args...>)
1397bdd1243dSDimitry Andric      : __impl_(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
13980b57cec5SDimitry Andric
1399*06c3fb27SDimitry Andric  _LIBCPP_HIDE_FROM_ABI ~variant() = default;
14000b57cec5SDimitry Andric
1401*06c3fb27SDimitry Andric  _LIBCPP_HIDE_FROM_ABI constexpr variant& operator=(const variant&) = default;
1402*06c3fb27SDimitry Andric  _LIBCPP_HIDE_FROM_ABI constexpr variant& operator=(variant&&) = default;
14030b57cec5SDimitry Andric
14040b57cec5SDimitry Andric  template <
14050b57cec5SDimitry Andric      class _Arg,
1406bdd1243dSDimitry Andric      enable_if_t<!is_same_v<__remove_cvref_t<_Arg>, variant>, int> = 0,
14070b57cec5SDimitry Andric      class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,
14080b57cec5SDimitry Andric      size_t _Ip =
14090b57cec5SDimitry Andric          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
14100b57cec5SDimitry Andric      enable_if_t<is_assignable_v<_Tp&, _Arg> && is_constructible_v<_Tp, _Arg>,
14110b57cec5SDimitry Andric                  int> = 0>
1412bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
14130b57cec5SDimitry Andric  variant& operator=(_Arg&& __arg) noexcept(
14140b57cec5SDimitry Andric      is_nothrow_assignable_v<_Tp&, _Arg> &&
14150b57cec5SDimitry Andric      is_nothrow_constructible_v<_Tp, _Arg>) {
1416bdd1243dSDimitry Andric    __impl_.template __assign<_Ip>(_VSTD::forward<_Arg>(__arg));
14170b57cec5SDimitry Andric    return *this;
14180b57cec5SDimitry Andric  }
14190b57cec5SDimitry Andric
14200b57cec5SDimitry Andric  template <
14210b57cec5SDimitry Andric      size_t _Ip,
14220b57cec5SDimitry Andric      class... _Args,
14230b57cec5SDimitry Andric      enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
14240b57cec5SDimitry Andric      class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
14250b57cec5SDimitry Andric      enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
1426bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
14270b57cec5SDimitry Andric  _Tp& emplace(_Args&&... __args) {
1428bdd1243dSDimitry Andric    return __impl_.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
14290b57cec5SDimitry Andric  }
14300b57cec5SDimitry Andric
14310b57cec5SDimitry Andric  template <
14320b57cec5SDimitry Andric      size_t _Ip,
14330b57cec5SDimitry Andric      class _Up,
14340b57cec5SDimitry Andric      class... _Args,
14350b57cec5SDimitry Andric      enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
14360b57cec5SDimitry Andric      class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
14370b57cec5SDimitry Andric      enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
14380b57cec5SDimitry Andric                  int> = 0>
1439bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
14400b57cec5SDimitry Andric  _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
1441bdd1243dSDimitry Andric    return __impl_.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
14420b57cec5SDimitry Andric  }
14430b57cec5SDimitry Andric
14440b57cec5SDimitry Andric  template <
14450b57cec5SDimitry Andric      class _Tp,
14460b57cec5SDimitry Andric      class... _Args,
14470b57cec5SDimitry Andric      size_t _Ip =
14480b57cec5SDimitry Andric          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
14490b57cec5SDimitry Andric      enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
1450bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
14510b57cec5SDimitry Andric  _Tp& emplace(_Args&&... __args) {
1452bdd1243dSDimitry Andric    return __impl_.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
14530b57cec5SDimitry Andric  }
14540b57cec5SDimitry Andric
14550b57cec5SDimitry Andric  template <
14560b57cec5SDimitry Andric      class _Tp,
14570b57cec5SDimitry Andric      class _Up,
14580b57cec5SDimitry Andric      class... _Args,
14590b57cec5SDimitry Andric      size_t _Ip =
14600b57cec5SDimitry Andric          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
14610b57cec5SDimitry Andric      enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
14620b57cec5SDimitry Andric                  int> = 0>
1463bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
14640b57cec5SDimitry Andric  _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
1465bdd1243dSDimitry Andric    return __impl_.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
14660b57cec5SDimitry Andric  }
14670b57cec5SDimitry Andric
1468bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
14690b57cec5SDimitry Andric  constexpr bool valueless_by_exception() const noexcept {
1470bdd1243dSDimitry Andric    return __impl_.valueless_by_exception();
14710b57cec5SDimitry Andric  }
14720b57cec5SDimitry Andric
1473bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
1474bdd1243dSDimitry Andric  constexpr size_t index() const noexcept { return __impl_.index(); }
14750b57cec5SDimitry Andric
14760b57cec5SDimitry Andric  template <
14770b57cec5SDimitry Andric      bool _Dummy = true,
14780b57cec5SDimitry Andric      enable_if_t<
14790b57cec5SDimitry Andric          __all<(
14800b57cec5SDimitry Andric              __dependent_type<is_move_constructible<_Types>, _Dummy>::value &&
14810b57cec5SDimitry Andric              __dependent_type<is_swappable<_Types>, _Dummy>::value)...>::value,
14820b57cec5SDimitry Andric          int> = 0>
1483bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
14840b57cec5SDimitry Andric  void swap(variant& __that) noexcept(
14850b57cec5SDimitry Andric      __all<(is_nothrow_move_constructible_v<_Types> &&
14860b57cec5SDimitry Andric             is_nothrow_swappable_v<_Types>)...>::value) {
1487bdd1243dSDimitry Andric    __impl_.__swap(__that.__impl_);
14880b57cec5SDimitry Andric  }
14890b57cec5SDimitry Andric
14900b57cec5SDimitry Andricprivate:
1491bdd1243dSDimitry Andric  __variant_detail::__impl<_Types...> __impl_;
14920b57cec5SDimitry Andric
14930b57cec5SDimitry Andric  friend struct __variant_detail::__access::__variant;
14940b57cec5SDimitry Andric  friend struct __variant_detail::__visitation::__variant;
14950b57cec5SDimitry Andric};
14960b57cec5SDimitry Andric
14970b57cec5SDimitry Andrictemplate <size_t _Ip, class... _Types>
1498bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
14990b57cec5SDimitry Andricconstexpr bool __holds_alternative(const variant<_Types...>& __v) noexcept {
15000b57cec5SDimitry Andric  return __v.index() == _Ip;
15010b57cec5SDimitry Andric}
15020b57cec5SDimitry Andric
15030b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
1504bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15050b57cec5SDimitry Andricconstexpr bool holds_alternative(const variant<_Types...>& __v) noexcept {
1506bdd1243dSDimitry Andric  return std::__holds_alternative<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
15070b57cec5SDimitry Andric}
15080b57cec5SDimitry Andric
15090b57cec5SDimitry Andrictemplate <size_t _Ip, class _Vp>
1510bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15110b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
15120b57cec5SDimitry Andricconstexpr auto&& __generic_get(_Vp&& __v) {
15130b57cec5SDimitry Andric  using __variant_detail::__access::__variant;
1514bdd1243dSDimitry Andric  if (!std::__holds_alternative<_Ip>(__v)) {
15150b57cec5SDimitry Andric    __throw_bad_variant_access();
15160b57cec5SDimitry Andric  }
15170b57cec5SDimitry Andric  return __variant::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v)).__value;
15180b57cec5SDimitry Andric}
15190b57cec5SDimitry Andric
15200b57cec5SDimitry Andrictemplate <size_t _Ip, class... _Types>
1521bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15220b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
15230b57cec5SDimitry Andricconstexpr variant_alternative_t<_Ip, variant<_Types...>>& get(
15240b57cec5SDimitry Andric    variant<_Types...>& __v) {
15250b57cec5SDimitry Andric  static_assert(_Ip < sizeof...(_Types));
15260b57cec5SDimitry Andric  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1527bdd1243dSDimitry Andric  return std::__generic_get<_Ip>(__v);
15280b57cec5SDimitry Andric}
15290b57cec5SDimitry Andric
15300b57cec5SDimitry Andrictemplate <size_t _Ip, class... _Types>
1531bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15320b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
15330b57cec5SDimitry Andricconstexpr variant_alternative_t<_Ip, variant<_Types...>>&& get(
15340b57cec5SDimitry Andric    variant<_Types...>&& __v) {
15350b57cec5SDimitry Andric  static_assert(_Ip < sizeof...(_Types));
15360b57cec5SDimitry Andric  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1537bdd1243dSDimitry Andric  return std::__generic_get<_Ip>(_VSTD::move(__v));
15380b57cec5SDimitry Andric}
15390b57cec5SDimitry Andric
15400b57cec5SDimitry Andrictemplate <size_t _Ip, class... _Types>
1541bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15420b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
15430b57cec5SDimitry Andricconstexpr const variant_alternative_t<_Ip, variant<_Types...>>& get(
15440b57cec5SDimitry Andric    const variant<_Types...>& __v) {
15450b57cec5SDimitry Andric  static_assert(_Ip < sizeof...(_Types));
15460b57cec5SDimitry Andric  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1547bdd1243dSDimitry Andric  return std::__generic_get<_Ip>(__v);
15480b57cec5SDimitry Andric}
15490b57cec5SDimitry Andric
15500b57cec5SDimitry Andrictemplate <size_t _Ip, class... _Types>
1551bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15520b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
15530b57cec5SDimitry Andricconstexpr const variant_alternative_t<_Ip, variant<_Types...>>&& get(
15540b57cec5SDimitry Andric    const variant<_Types...>&& __v) {
15550b57cec5SDimitry Andric  static_assert(_Ip < sizeof...(_Types));
15560b57cec5SDimitry Andric  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1557bdd1243dSDimitry Andric  return std::__generic_get<_Ip>(_VSTD::move(__v));
15580b57cec5SDimitry Andric}
15590b57cec5SDimitry Andric
15600b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
1561bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15620b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
15630b57cec5SDimitry Andricconstexpr _Tp& get(variant<_Types...>& __v) {
15640b57cec5SDimitry Andric  static_assert(!is_void_v<_Tp>);
15650b57cec5SDimitry Andric  return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
15660b57cec5SDimitry Andric}
15670b57cec5SDimitry Andric
15680b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
1569bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15700b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
15710b57cec5SDimitry Andricconstexpr _Tp&& get(variant<_Types...>&& __v) {
15720b57cec5SDimitry Andric  static_assert(!is_void_v<_Tp>);
15730b57cec5SDimitry Andric  return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(
15740b57cec5SDimitry Andric      _VSTD::move(__v));
15750b57cec5SDimitry Andric}
15760b57cec5SDimitry Andric
15770b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
1578bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15790b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
15800b57cec5SDimitry Andricconstexpr const _Tp& get(const variant<_Types...>& __v) {
15810b57cec5SDimitry Andric  static_assert(!is_void_v<_Tp>);
15820b57cec5SDimitry Andric  return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
15830b57cec5SDimitry Andric}
15840b57cec5SDimitry Andric
15850b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
1586bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15870b57cec5SDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
15880b57cec5SDimitry Andricconstexpr const _Tp&& get(const variant<_Types...>&& __v) {
15890b57cec5SDimitry Andric  static_assert(!is_void_v<_Tp>);
15900b57cec5SDimitry Andric  return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(
15910b57cec5SDimitry Andric      _VSTD::move(__v));
15920b57cec5SDimitry Andric}
15930b57cec5SDimitry Andric
15940b57cec5SDimitry Andrictemplate <size_t _Ip, class _Vp>
1595bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
15960b57cec5SDimitry Andricconstexpr auto* __generic_get_if(_Vp* __v) noexcept {
15970b57cec5SDimitry Andric  using __variant_detail::__access::__variant;
1598bdd1243dSDimitry Andric  return __v && std::__holds_alternative<_Ip>(*__v)
15990b57cec5SDimitry Andric             ? _VSTD::addressof(__variant::__get_alt<_Ip>(*__v).__value)
16000b57cec5SDimitry Andric             : nullptr;
16010b57cec5SDimitry Andric}
16020b57cec5SDimitry Andric
16030b57cec5SDimitry Andrictemplate <size_t _Ip, class... _Types>
1604bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
16050b57cec5SDimitry Andricconstexpr add_pointer_t<variant_alternative_t<_Ip, variant<_Types...>>>
16060b57cec5SDimitry Andricget_if(variant<_Types...>* __v) noexcept {
16070b57cec5SDimitry Andric  static_assert(_Ip < sizeof...(_Types));
16080b57cec5SDimitry Andric  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1609bdd1243dSDimitry Andric  return std::__generic_get_if<_Ip>(__v);
16100b57cec5SDimitry Andric}
16110b57cec5SDimitry Andric
16120b57cec5SDimitry Andrictemplate <size_t _Ip, class... _Types>
1613bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
16140b57cec5SDimitry Andricconstexpr add_pointer_t<const variant_alternative_t<_Ip, variant<_Types...>>>
16150b57cec5SDimitry Andricget_if(const variant<_Types...>* __v) noexcept {
16160b57cec5SDimitry Andric  static_assert(_Ip < sizeof...(_Types));
16170b57cec5SDimitry Andric  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1618bdd1243dSDimitry Andric  return std::__generic_get_if<_Ip>(__v);
16190b57cec5SDimitry Andric}
16200b57cec5SDimitry Andric
16210b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
1622bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
16230b57cec5SDimitry Andricconstexpr add_pointer_t<_Tp>
16240b57cec5SDimitry Andricget_if(variant<_Types...>* __v) noexcept {
16250b57cec5SDimitry Andric  static_assert(!is_void_v<_Tp>);
16260b57cec5SDimitry Andric  return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
16270b57cec5SDimitry Andric}
16280b57cec5SDimitry Andric
16290b57cec5SDimitry Andrictemplate <class _Tp, class... _Types>
1630bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
16310b57cec5SDimitry Andricconstexpr add_pointer_t<const _Tp>
16320b57cec5SDimitry Andricget_if(const variant<_Types...>* __v) noexcept {
16330b57cec5SDimitry Andric  static_assert(!is_void_v<_Tp>);
16340b57cec5SDimitry Andric  return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
16350b57cec5SDimitry Andric}
16360b57cec5SDimitry Andric
16370b57cec5SDimitry Andrictemplate <class _Operator>
16380b57cec5SDimitry Andricstruct __convert_to_bool {
16390b57cec5SDimitry Andric  template <class _T1, class _T2>
1640bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
1641bdd1243dSDimitry Andric  constexpr bool operator()(_T1 && __t1, _T2&& __t2) const {
1642e8d8bef9SDimitry Andric    static_assert(is_convertible<decltype(_Operator{}(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2))), bool>::value,
16430b57cec5SDimitry Andric        "the relational operator does not return a type which is implicitly convertible to bool");
16440b57cec5SDimitry Andric    return _Operator{}(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
16450b57cec5SDimitry Andric  }
16460b57cec5SDimitry Andric};
16470b57cec5SDimitry Andric
16480b57cec5SDimitry Andrictemplate <class... _Types>
1649bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
16500b57cec5SDimitry Andricconstexpr bool operator==(const variant<_Types...>& __lhs,
16510b57cec5SDimitry Andric                          const variant<_Types...>& __rhs) {
16520b57cec5SDimitry Andric  using __variant_detail::__visitation::__variant;
16530b57cec5SDimitry Andric  if (__lhs.index() != __rhs.index()) return false;
16540b57cec5SDimitry Andric  if (__lhs.valueless_by_exception()) return true;
16550b57cec5SDimitry Andric  return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<equal_to<>>{}, __lhs, __rhs);
16560b57cec5SDimitry Andric}
16570b57cec5SDimitry Andric
1658*06c3fb27SDimitry Andric#  if _LIBCPP_STD_VER >= 20
1659bdd1243dSDimitry Andric
1660bdd1243dSDimitry Andrictemplate <class... _Types> requires (three_way_comparable<_Types> && ...)
1661bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI constexpr common_comparison_category_t<compare_three_way_result_t<_Types>...>
1662bdd1243dSDimitry Andricoperator<=>(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {
1663bdd1243dSDimitry Andric  using __variant_detail::__visitation::__variant;
1664bdd1243dSDimitry Andric  using __result_t = common_comparison_category_t<compare_three_way_result_t<_Types>...>;
1665bdd1243dSDimitry Andric  if (__lhs.valueless_by_exception() && __rhs.valueless_by_exception())
1666bdd1243dSDimitry Andric    return strong_ordering::equal;
1667bdd1243dSDimitry Andric  if (__lhs.valueless_by_exception())
1668bdd1243dSDimitry Andric    return strong_ordering::less;
1669bdd1243dSDimitry Andric  if (__rhs.valueless_by_exception())
1670bdd1243dSDimitry Andric    return strong_ordering::greater;
1671bdd1243dSDimitry Andric  if (auto __c = __lhs.index() <=> __rhs.index(); __c != 0)
1672bdd1243dSDimitry Andric    return __c;
1673bdd1243dSDimitry Andric  auto __three_way = []<class _Type>(const _Type& __v, const _Type& __w) -> __result_t { return __v <=> __w; };
1674bdd1243dSDimitry Andric  return __variant::__visit_value_at(__lhs.index(), __three_way, __lhs, __rhs);
1675bdd1243dSDimitry Andric}
1676bdd1243dSDimitry Andric
1677*06c3fb27SDimitry Andric#  endif // _LIBCPP_STD_VER >= 20
1678bdd1243dSDimitry Andric
16790b57cec5SDimitry Andrictemplate <class... _Types>
1680bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
16810b57cec5SDimitry Andricconstexpr bool operator!=(const variant<_Types...>& __lhs,
16820b57cec5SDimitry Andric                          const variant<_Types...>& __rhs) {
16830b57cec5SDimitry Andric  using __variant_detail::__visitation::__variant;
16840b57cec5SDimitry Andric  if (__lhs.index() != __rhs.index()) return true;
16850b57cec5SDimitry Andric  if (__lhs.valueless_by_exception()) return false;
16860b57cec5SDimitry Andric  return __variant::__visit_value_at(
16870b57cec5SDimitry Andric      __lhs.index(), __convert_to_bool<not_equal_to<>>{}, __lhs, __rhs);
16880b57cec5SDimitry Andric}
16890b57cec5SDimitry Andric
16900b57cec5SDimitry Andrictemplate <class... _Types>
1691bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
16920b57cec5SDimitry Andricconstexpr bool operator<(const variant<_Types...>& __lhs,
16930b57cec5SDimitry Andric                         const variant<_Types...>& __rhs) {
16940b57cec5SDimitry Andric  using __variant_detail::__visitation::__variant;
16950b57cec5SDimitry Andric  if (__rhs.valueless_by_exception()) return false;
16960b57cec5SDimitry Andric  if (__lhs.valueless_by_exception()) return true;
16970b57cec5SDimitry Andric  if (__lhs.index() < __rhs.index()) return true;
16980b57cec5SDimitry Andric  if (__lhs.index() > __rhs.index()) return false;
16990b57cec5SDimitry Andric  return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<less<>>{}, __lhs, __rhs);
17000b57cec5SDimitry Andric}
17010b57cec5SDimitry Andric
17020b57cec5SDimitry Andrictemplate <class... _Types>
1703bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
17040b57cec5SDimitry Andricconstexpr bool operator>(const variant<_Types...>& __lhs,
17050b57cec5SDimitry Andric                         const variant<_Types...>& __rhs) {
17060b57cec5SDimitry Andric  using __variant_detail::__visitation::__variant;
17070b57cec5SDimitry Andric  if (__lhs.valueless_by_exception()) return false;
17080b57cec5SDimitry Andric  if (__rhs.valueless_by_exception()) return true;
17090b57cec5SDimitry Andric  if (__lhs.index() > __rhs.index()) return true;
17100b57cec5SDimitry Andric  if (__lhs.index() < __rhs.index()) return false;
17110b57cec5SDimitry Andric  return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<greater<>>{}, __lhs, __rhs);
17120b57cec5SDimitry Andric}
17130b57cec5SDimitry Andric
17140b57cec5SDimitry Andrictemplate <class... _Types>
1715bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
17160b57cec5SDimitry Andricconstexpr bool operator<=(const variant<_Types...>& __lhs,
17170b57cec5SDimitry Andric                          const variant<_Types...>& __rhs) {
17180b57cec5SDimitry Andric  using __variant_detail::__visitation::__variant;
17190b57cec5SDimitry Andric  if (__lhs.valueless_by_exception()) return true;
17200b57cec5SDimitry Andric  if (__rhs.valueless_by_exception()) return false;
17210b57cec5SDimitry Andric  if (__lhs.index() < __rhs.index()) return true;
17220b57cec5SDimitry Andric  if (__lhs.index() > __rhs.index()) return false;
17230b57cec5SDimitry Andric  return __variant::__visit_value_at(
17240b57cec5SDimitry Andric      __lhs.index(), __convert_to_bool<less_equal<>>{}, __lhs, __rhs);
17250b57cec5SDimitry Andric}
17260b57cec5SDimitry Andric
17270b57cec5SDimitry Andrictemplate <class... _Types>
1728bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
17290b57cec5SDimitry Andricconstexpr bool operator>=(const variant<_Types...>& __lhs,
17300b57cec5SDimitry Andric                          const variant<_Types...>& __rhs) {
17310b57cec5SDimitry Andric  using __variant_detail::__visitation::__variant;
17320b57cec5SDimitry Andric  if (__rhs.valueless_by_exception()) return true;
17330b57cec5SDimitry Andric  if (__lhs.valueless_by_exception()) return false;
17340b57cec5SDimitry Andric  if (__lhs.index() > __rhs.index()) return true;
17350b57cec5SDimitry Andric  if (__lhs.index() < __rhs.index()) return false;
17360b57cec5SDimitry Andric  return __variant::__visit_value_at(
17370b57cec5SDimitry Andric      __lhs.index(), __convert_to_bool<greater_equal<>>{}, __lhs, __rhs);
17380b57cec5SDimitry Andric}
17390b57cec5SDimitry Andric
1740e8d8bef9SDimitry Andrictemplate <class... _Vs>
1741bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
1742bdd1243dSDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
1743bdd1243dSDimitry Andricconstexpr void __throw_if_valueless(_Vs&&... __vs) {
1744fe6060f1SDimitry Andric  const bool __valueless =
1745fe6060f1SDimitry Andric      (... || _VSTD::__as_variant(__vs).valueless_by_exception());
1746e8d8bef9SDimitry Andric  if (__valueless) {
1747e8d8bef9SDimitry Andric    __throw_bad_variant_access();
1748e8d8bef9SDimitry Andric  }
1749e8d8bef9SDimitry Andric}
1750e8d8bef9SDimitry Andric
1751fe6060f1SDimitry Andrictemplate <
1752fe6060f1SDimitry Andric    class _Visitor, class... _Vs,
1753bdd1243dSDimitry Andric    typename = void_t<decltype(_VSTD::__as_variant(std::declval<_Vs>()))...> >
1754bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
1755bdd1243dSDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
1756bdd1243dSDimitry Andricconstexpr decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs) {
17570b57cec5SDimitry Andric  using __variant_detail::__visitation::__variant;
1758e8d8bef9SDimitry Andric  _VSTD::__throw_if_valueless(_VSTD::forward<_Vs>(__vs)...);
17590b57cec5SDimitry Andric  return __variant::__visit_value(_VSTD::forward<_Visitor>(__visitor),
17600b57cec5SDimitry Andric                                  _VSTD::forward<_Vs>(__vs)...);
17610b57cec5SDimitry Andric}
17620b57cec5SDimitry Andric
1763*06c3fb27SDimitry Andric#if _LIBCPP_STD_VER >= 20
1764fe6060f1SDimitry Andrictemplate <
1765fe6060f1SDimitry Andric    class _Rp, class _Visitor, class... _Vs,
1766bdd1243dSDimitry Andric    typename = void_t<decltype(_VSTD::__as_variant(std::declval<_Vs>()))...> >
1767bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
1768bdd1243dSDimitry Andric_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
1769bdd1243dSDimitry Andricconstexpr _Rp visit(_Visitor&& __visitor, _Vs&&... __vs) {
1770e8d8bef9SDimitry Andric  using __variant_detail::__visitation::__variant;
1771e8d8bef9SDimitry Andric  _VSTD::__throw_if_valueless(_VSTD::forward<_Vs>(__vs)...);
1772e8d8bef9SDimitry Andric  return __variant::__visit_value<_Rp>(_VSTD::forward<_Visitor>(__visitor),
1773e8d8bef9SDimitry Andric                                       _VSTD::forward<_Vs>(__vs)...);
1774e8d8bef9SDimitry Andric}
1775e8d8bef9SDimitry Andric#endif
1776e8d8bef9SDimitry Andric
17770b57cec5SDimitry Andrictemplate <class... _Types>
1778bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
1779349cc55cSDimitry Andricauto swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs)
1780349cc55cSDimitry Andric  noexcept(noexcept(__lhs.swap(__rhs)))
1781349cc55cSDimitry Andric  -> decltype(      __lhs.swap(__rhs))
1782349cc55cSDimitry Andric  { return          __lhs.swap(__rhs); }
17830b57cec5SDimitry Andric
17840b57cec5SDimitry Andrictemplate <class... _Types>
17850b57cec5SDimitry Andricstruct _LIBCPP_TEMPLATE_VIS hash<
17860b57cec5SDimitry Andric    __enable_hash_helper<variant<_Types...>, remove_const_t<_Types>...>> {
17870b57cec5SDimitry Andric  using argument_type = variant<_Types...>;
17880b57cec5SDimitry Andric  using result_type = size_t;
17890b57cec5SDimitry Andric
1790bdd1243dSDimitry Andric  _LIBCPP_HIDE_FROM_ABI
17910b57cec5SDimitry Andric  result_type operator()(const argument_type& __v) const {
17920b57cec5SDimitry Andric    using __variant_detail::__visitation::__variant;
17930b57cec5SDimitry Andric    size_t __res =
17940b57cec5SDimitry Andric        __v.valueless_by_exception()
17950b57cec5SDimitry Andric               ? 299792458 // Random value chosen by the universe upon creation
17960b57cec5SDimitry Andric               : __variant::__visit_alt(
17970b57cec5SDimitry Andric                     [](const auto& __alt) {
1798bdd1243dSDimitry Andric                       using __alt_type = __remove_cvref_t<decltype(__alt)>;
17990b57cec5SDimitry Andric                       using __value_type = remove_const_t<
18000b57cec5SDimitry Andric                         typename __alt_type::__value_type>;
18010b57cec5SDimitry Andric                       return hash<__value_type>{}(__alt.__value);
18020b57cec5SDimitry Andric                     },
18030b57cec5SDimitry Andric                     __v);
1804bdd1243dSDimitry Andric    return std::__hash_combine(__res, hash<size_t>{}(__v.index()));
18050b57cec5SDimitry Andric  }
18060b57cec5SDimitry Andric};
18070b57cec5SDimitry Andric
1808fe6060f1SDimitry Andric// __unchecked_get is the same as std::get, except, it is UB to use it with the wrong
1809fe6060f1SDimitry Andric// type whereas std::get will throw or returning nullptr. This makes it faster than
1810fe6060f1SDimitry Andric// std::get.
1811fe6060f1SDimitry Andrictemplate <size_t _Ip, class _Vp>
1812bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
1813fe6060f1SDimitry Andricconstexpr auto&& __unchecked_get(_Vp&& __v) noexcept {
1814fe6060f1SDimitry Andric  using __variant_detail::__access::__variant;
1815fe6060f1SDimitry Andric  return __variant::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v)).__value;
18160b57cec5SDimitry Andric}
1817fe6060f1SDimitry Andric
1818fe6060f1SDimitry Andrictemplate <class _Tp, class... _Types>
1819bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
1820fe6060f1SDimitry Andricconstexpr auto&& __unchecked_get(const variant<_Types...>& __v) noexcept {
1821bdd1243dSDimitry Andric  return std::__unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
1822fe6060f1SDimitry Andric}
1823fe6060f1SDimitry Andric
1824fe6060f1SDimitry Andrictemplate <class _Tp, class... _Types>
1825bdd1243dSDimitry Andric_LIBCPP_HIDE_FROM_ABI
1826fe6060f1SDimitry Andricconstexpr auto&& __unchecked_get(variant<_Types...>& __v) noexcept {
1827bdd1243dSDimitry Andric  return std::__unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
1828fe6060f1SDimitry Andric}
18290b57cec5SDimitry Andric
1830*06c3fb27SDimitry Andric#endif // _LIBCPP_STD_VER >= 17
18310b57cec5SDimitry Andric
18320b57cec5SDimitry Andric_LIBCPP_END_NAMESPACE_STD
18330b57cec5SDimitry Andric
18340b57cec5SDimitry Andric_LIBCPP_POP_MACROS
18350b57cec5SDimitry Andric
1836bdd1243dSDimitry Andric#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1837*06c3fb27SDimitry Andric#  include <exception>
1838bdd1243dSDimitry Andric#  include <type_traits>
1839bdd1243dSDimitry Andric#  include <typeinfo>
1840bdd1243dSDimitry Andric#  include <utility>
1841bdd1243dSDimitry Andric#endif
1842bdd1243dSDimitry Andric
18430b57cec5SDimitry Andric#endif // _LIBCPP_VARIANT
1844