// -*- C++ -*- //===------------------------------ variant -------------------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// #ifndef _LIBCPP_VARIANT #define _LIBCPP_VARIANT /* variant synopsis namespace std { // 20.7.2, class template variant template class variant { public: // 20.7.2.1, constructors constexpr variant() noexcept(see below); variant(const variant&); // constexpr in C++20 variant(variant&&) noexcept(see below); // constexpr in C++20 template constexpr variant(T&&) noexcept(see below); template constexpr explicit variant(in_place_type_t, Args&&...); template constexpr explicit variant( in_place_type_t, initializer_list, Args&&...); template constexpr explicit variant(in_place_index_t, Args&&...); template constexpr explicit variant( in_place_index_t, initializer_list, Args&&...); // 20.7.2.2, destructor ~variant(); // 20.7.2.3, assignment variant& operator=(const variant&); // constexpr in C++20 variant& operator=(variant&&) noexcept(see below); // constexpr in C++20 template variant& operator=(T&&) noexcept(see below); // 20.7.2.4, modifiers template T& emplace(Args&&...); template T& emplace(initializer_list, Args&&...); template variant_alternative_t& emplace(Args&&...); template variant_alternative_t& emplace(initializer_list, Args&&...); // 20.7.2.5, value status constexpr bool valueless_by_exception() const noexcept; constexpr size_t index() const noexcept; // 20.7.2.6, swap void swap(variant&) noexcept(see below); }; // 20.7.3, variant helper classes template struct variant_size; // undefined template inline constexpr size_t variant_size_v = variant_size::value; template struct variant_size; template struct variant_size; template struct variant_size; template struct variant_size>; template struct variant_alternative; // undefined template using variant_alternative_t = typename variant_alternative::type; template struct variant_alternative; template struct variant_alternative; template struct variant_alternative; template struct variant_alternative>; inline constexpr size_t variant_npos = -1; // 20.7.4, value access template constexpr bool holds_alternative(const variant&) noexcept; template constexpr variant_alternative_t>& get(variant&); template constexpr variant_alternative_t>&& get(variant&&); template constexpr variant_alternative_t> const& get(const variant&); template constexpr variant_alternative_t> const&& get(const variant&&); template constexpr T& get(variant&); template constexpr T&& get(variant&&); template constexpr const T& get(const variant&); template constexpr const T&& get(const variant&&); template constexpr add_pointer_t>> get_if(variant*) noexcept; template constexpr add_pointer_t>> get_if(const variant*) noexcept; template constexpr add_pointer_t get_if(variant*) noexcept; template constexpr add_pointer_t get_if(const variant*) noexcept; // 20.7.5, relational operators template constexpr bool operator==(const variant&, const variant&); template constexpr bool operator!=(const variant&, const variant&); template constexpr bool operator<(const variant&, const variant&); template constexpr bool operator>(const variant&, const variant&); template constexpr bool operator<=(const variant&, const variant&); template constexpr bool operator>=(const variant&, const variant&); // 20.7.6, visitation template constexpr see below visit(Visitor&&, Variants&&...); // 20.7.7, class monostate struct monostate; // 20.7.8, monostate relational operators constexpr bool operator<(monostate, monostate) noexcept; constexpr bool operator>(monostate, monostate) noexcept; constexpr bool operator<=(monostate, monostate) noexcept; constexpr bool operator>=(monostate, monostate) noexcept; constexpr bool operator==(monostate, monostate) noexcept; constexpr bool operator!=(monostate, monostate) noexcept; // 20.7.9, specialized algorithms template void swap(variant&, variant&) noexcept(see below); // 20.7.10, class bad_variant_access class bad_variant_access; // 20.7.11, hash support template struct hash; template struct hash>; template <> struct hash; } // namespace std */ #include <__config> #include <__tuple> #include #include #include #include #include #include #include #include #include #include #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) #pragma GCC system_header #endif _LIBCPP_PUSH_MACROS #include <__undef_macros> namespace std { // explicitly not using versioning namespace class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS bad_variant_access : public exception { public: virtual const char* what() const _NOEXCEPT; }; } // namespace std _LIBCPP_BEGIN_NAMESPACE_STD #if _LIBCPP_STD_VER > 14 _LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS void __throw_bad_variant_access() { #ifndef _LIBCPP_NO_EXCEPTIONS throw bad_variant_access(); #else _VSTD::abort(); #endif } template class _LIBCPP_TEMPLATE_VIS variant; template struct _LIBCPP_TEMPLATE_VIS variant_size; template _LIBCPP_INLINE_VAR constexpr size_t variant_size_v = variant_size<_Tp>::value; template struct _LIBCPP_TEMPLATE_VIS variant_size : variant_size<_Tp> {}; template struct _LIBCPP_TEMPLATE_VIS variant_size : variant_size<_Tp> {}; template struct _LIBCPP_TEMPLATE_VIS variant_size : variant_size<_Tp> {}; template struct _LIBCPP_TEMPLATE_VIS variant_size> : integral_constant {}; template struct _LIBCPP_TEMPLATE_VIS variant_alternative; template using variant_alternative_t = typename variant_alternative<_Ip, _Tp>::type; template struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const _Tp> : add_const> {}; template struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, volatile _Tp> : add_volatile> {}; template struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const volatile _Tp> : add_cv> {}; template struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, variant<_Types...>> { static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>"); using type = __type_pack_element<_Ip, _Types...>; }; _LIBCPP_INLINE_VAR constexpr size_t variant_npos = static_cast(-1); constexpr int __choose_index_type(unsigned int __num_elem) { if (__num_elem < std::numeric_limits::max()) return 0; if (__num_elem < std::numeric_limits::max()) return 1; return 2; } template using __variant_index_t = #ifndef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION unsigned int; #else std::tuple_element_t< __choose_index_type(_NumAlts), std::tuple >; #endif template constexpr _IndexType __variant_npos = static_cast<_IndexType>(-1); namespace __find_detail { template inline _LIBCPP_INLINE_VISIBILITY constexpr size_t __find_index() { constexpr bool __matches[] = {is_same_v<_Tp, _Types>...}; size_t __result = __not_found; for (size_t __i = 0; __i < sizeof...(_Types); ++__i) { if (__matches[__i]) { if (__result != __not_found) { return __ambiguous; } __result = __i; } } return __result; } template struct __find_unambiguous_index_sfinae_impl : integral_constant {}; template <> struct __find_unambiguous_index_sfinae_impl<__not_found> {}; template <> struct __find_unambiguous_index_sfinae_impl<__ambiguous> {}; template struct __find_unambiguous_index_sfinae : __find_unambiguous_index_sfinae_impl<__find_index<_Tp, _Types...>()> {}; } // namespace __find_detail namespace __variant_detail { struct __valueless_t {}; enum class _Trait { _TriviallyAvailable, _Available, _Unavailable }; template class _IsTriviallyAvailable, template class _IsAvailable> constexpr _Trait __trait = _IsTriviallyAvailable<_Tp>::value ? _Trait::_TriviallyAvailable : _IsAvailable<_Tp>::value ? _Trait::_Available : _Trait::_Unavailable; inline _LIBCPP_INLINE_VISIBILITY constexpr _Trait __common_trait(initializer_list<_Trait> __traits) { _Trait __result = _Trait::_TriviallyAvailable; for (_Trait __t : __traits) { if (static_cast(__t) > static_cast(__result)) { __result = __t; } } return __result; } template struct __traits { static constexpr _Trait __copy_constructible_trait = __common_trait({__trait<_Types, is_trivially_copy_constructible, is_copy_constructible>...}); static constexpr _Trait __move_constructible_trait = __common_trait({__trait<_Types, is_trivially_move_constructible, is_move_constructible>...}); static constexpr _Trait __copy_assignable_trait = __common_trait( {__copy_constructible_trait, __trait<_Types, is_trivially_copy_assignable, is_copy_assignable>...}); static constexpr _Trait __move_assignable_trait = __common_trait( {__move_constructible_trait, __trait<_Types, is_trivially_move_assignable, is_move_assignable>...}); static constexpr _Trait __destructible_trait = __common_trait( {__trait<_Types, is_trivially_destructible, is_destructible>...}); }; namespace __access { struct __union { template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<0>) { return _VSTD::forward<_Vp>(__v).__head; } template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<_Ip>) { return __get_alt(_VSTD::forward<_Vp>(__v).__tail, in_place_index<_Ip - 1>); } }; struct __base { template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto&& __get_alt(_Vp&& __v) { return __union::__get_alt(_VSTD::forward<_Vp>(__v).__data, in_place_index<_Ip>); } }; struct __variant { template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto&& __get_alt(_Vp&& __v) { return __base::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v).__impl); } }; } // namespace __access namespace __visitation { struct __base { template inline _LIBCPP_INLINE_VISIBILITY static constexpr decltype(auto) __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) { constexpr auto __fdiagonal = __make_fdiagonal<_Visitor&&, decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>(); return __fdiagonal[__index](_VSTD::forward<_Visitor>(__visitor), _VSTD::forward<_Vs>(__vs).__as_base()...); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) { constexpr auto __fmatrix = __make_fmatrix<_Visitor&&, decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>(); return __at(__fmatrix, __vs.index()...)( _VSTD::forward<_Visitor>(__visitor), _VSTD::forward<_Vs>(__vs).__as_base()...); } private: template inline _LIBCPP_INLINE_VISIBILITY static constexpr const _Tp& __at(const _Tp& __elem) { return __elem; } template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto&& __at(const array<_Tp, _Np>& __elems, size_t __index, _Indices... __indices) { return __at(__elems[__index], __indices...); } template static constexpr void __std_visit_visitor_return_type_check() { static_assert( __all...>::value, "`std::visit` requires the visitor to have a single return type."); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto __make_farray(_Fs&&... __fs) { __std_visit_visitor_return_type_check<__uncvref_t<_Fs>...>(); using __result = array...>, sizeof...(_Fs)>; return __result{{_VSTD::forward<_Fs>(__fs)...}}; } template struct __dispatcher { template inline _LIBCPP_INLINE_VISIBILITY static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) { return __invoke_constexpr( static_cast<_Fp>(__f), __access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...); } }; template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto __make_dispatch(index_sequence<_Is...>) { return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>; } template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto __make_fdiagonal_impl() { return __make_dispatch<_Fp, _Vs...>( index_sequence<(__identity<_Vs>{}, _Ip)...>{}); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) { return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto __make_fdiagonal() { constexpr size_t _Np = __uncvref_t<_Vp>::__size(); static_assert(__all<(_Np == __uncvref_t<_Vs>::__size())...>::value); return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<_Np>{}); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) { return __make_dispatch<_Fp, _Vs...>(__is); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto __make_fmatrix_impl(index_sequence<_Is...>, index_sequence<_Js...>, _Ls... __ls) { return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>( index_sequence<_Is..., _Js>{}, __ls...)...); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto __make_fmatrix() { return __make_fmatrix_impl<_Fp, _Vs...>( index_sequence<>{}, make_index_sequence<__uncvref_t<_Vs>::__size()>{}...); } }; struct __variant { template inline _LIBCPP_INLINE_VISIBILITY static constexpr decltype(auto) __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) { return __base::__visit_alt_at(__index, _VSTD::forward<_Visitor>(__visitor), _VSTD::forward<_Vs>(__vs).__impl...); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) { return __base::__visit_alt(_VSTD::forward<_Visitor>(__visitor), _VSTD::forward<_Vs>(__vs).__impl...); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr decltype(auto) __visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) { return __visit_alt_at( __index, __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)), _VSTD::forward<_Vs>(__vs)...); } template inline _LIBCPP_INLINE_VISIBILITY static constexpr decltype(auto) __visit_value(_Visitor&& __visitor, _Vs&&... __vs) { return __visit_alt( __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)), _VSTD::forward<_Vs>(__vs)...); } private: template static constexpr void __std_visit_exhaustive_visitor_check() { static_assert(is_invocable_v<_Visitor, _Values...>, "`std::visit` requires the visitor to be exhaustive."); } template struct __value_visitor { template inline _LIBCPP_INLINE_VISIBILITY constexpr decltype(auto) operator()(_Alts&&... __alts) const { __std_visit_exhaustive_visitor_check< _Visitor, decltype((_VSTD::forward<_Alts>(__alts).__value))...>(); return __invoke_constexpr(_VSTD::forward<_Visitor>(__visitor), _VSTD::forward<_Alts>(__alts).__value...); } _Visitor&& __visitor; }; template inline _LIBCPP_INLINE_VISIBILITY static constexpr auto __make_value_visitor(_Visitor&& __visitor) { return __value_visitor<_Visitor>{_VSTD::forward<_Visitor>(__visitor)}; } }; } // namespace __visitation template struct _LIBCPP_TEMPLATE_VIS __alt { using __value_type = _Tp; template inline _LIBCPP_INLINE_VISIBILITY explicit constexpr __alt(in_place_t, _Args&&... __args) : __value(_VSTD::forward<_Args>(__args)...) {} __value_type __value; }; template <_Trait _DestructibleTrait, size_t _Index, class... _Types> union _LIBCPP_TEMPLATE_VIS __union; template <_Trait _DestructibleTrait, size_t _Index> union _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {}; #define _LIBCPP_VARIANT_UNION(destructible_trait, destructor) \ template \ union _LIBCPP_TEMPLATE_VIS __union { \ public: \ inline _LIBCPP_INLINE_VISIBILITY \ explicit constexpr __union(__valueless_t) noexcept : __dummy{} {} \ \ template \ inline _LIBCPP_INLINE_VISIBILITY \ explicit constexpr __union(in_place_index_t<0>, _Args&&... __args) \ : __head(in_place, _VSTD::forward<_Args>(__args)...) {} \ \ template \ inline _LIBCPP_INLINE_VISIBILITY \ explicit constexpr __union(in_place_index_t<_Ip>, _Args&&... __args) \ : __tail(in_place_index<_Ip - 1>, _VSTD::forward<_Args>(__args)...) {} \ \ __union(const __union&) = default; \ __union(__union&&) = default; \ \ destructor \ \ __union& operator=(const __union&) = default; \ __union& operator=(__union&&) = default; \ \ private: \ char __dummy; \ __alt<_Index, _Tp> __head; \ __union __tail; \ \ friend struct __access::__union; \ } _LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable, ~__union() = default;); _LIBCPP_VARIANT_UNION(_Trait::_Available, ~__union() {}); _LIBCPP_VARIANT_UNION(_Trait::_Unavailable, ~__union() = delete;); #undef _LIBCPP_VARIANT_UNION template <_Trait _DestructibleTrait, class... _Types> class _LIBCPP_TEMPLATE_VIS __base { public: using __index_t = __variant_index_t; inline _LIBCPP_INLINE_VISIBILITY explicit constexpr __base(__valueless_t tag) noexcept : __data(tag), __index(__variant_npos<__index_t>) {} template inline _LIBCPP_INLINE_VISIBILITY explicit constexpr __base(in_place_index_t<_Ip>, _Args&&... __args) : __data(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...), __index(_Ip) {} inline _LIBCPP_INLINE_VISIBILITY constexpr bool valueless_by_exception() const noexcept { return index() == variant_npos; } inline _LIBCPP_INLINE_VISIBILITY constexpr size_t index() const noexcept { return __index == __variant_npos<__index_t> ? variant_npos : __index; } protected: inline _LIBCPP_INLINE_VISIBILITY constexpr auto&& __as_base() & { return *this; } inline _LIBCPP_INLINE_VISIBILITY constexpr auto&& __as_base() && { return _VSTD::move(*this); } inline _LIBCPP_INLINE_VISIBILITY constexpr auto&& __as_base() const & { return *this; } inline _LIBCPP_INLINE_VISIBILITY constexpr auto&& __as_base() const && { return _VSTD::move(*this); } inline _LIBCPP_INLINE_VISIBILITY static constexpr size_t __size() { return sizeof...(_Types); } __union<_DestructibleTrait, 0, _Types...> __data; __index_t __index; friend struct __access::__base; friend struct __visitation::__base; }; template class _LIBCPP_TEMPLATE_VIS __destructor; #define _LIBCPP_VARIANT_DESTRUCTOR(destructible_trait, destructor, destroy) \ template \ class _LIBCPP_TEMPLATE_VIS __destructor<__traits<_Types...>, \ destructible_trait> \ : public __base { \ using __base_type = __base; \ using __index_t = typename __base_type::__index_t; \ \ public: \ using __base_type::__base_type; \ using __base_type::operator=; \ \ __destructor(const __destructor&) = default; \ __destructor(__destructor&&) = default; \ destructor \ __destructor& operator=(const __destructor&) = default; \ __destructor& operator=(__destructor&&) = default; \ \ protected: \ inline _LIBCPP_INLINE_VISIBILITY \ destroy \ } _LIBCPP_VARIANT_DESTRUCTOR( _Trait::_TriviallyAvailable, ~__destructor() = default;, void __destroy() noexcept { this->__index = __variant_npos<__index_t>; }); _LIBCPP_VARIANT_DESTRUCTOR( _Trait::_Available, ~__destructor() { __destroy(); }, void __destroy() noexcept { if (!this->valueless_by_exception()) { __visitation::__base::__visit_alt( [](auto& __alt) noexcept { using __alt_type = __uncvref_t; __alt.~__alt_type(); }, *this); } this->__index = __variant_npos<__index_t>; }); _LIBCPP_VARIANT_DESTRUCTOR( _Trait::_Unavailable, ~__destructor() = delete;, void __destroy() noexcept = delete;); #undef _LIBCPP_VARIANT_DESTRUCTOR template class _LIBCPP_TEMPLATE_VIS __constructor : public __destructor<_Traits> { using __base_type = __destructor<_Traits>; public: using __base_type::__base_type; using __base_type::operator=; protected: template inline _LIBCPP_INLINE_VISIBILITY static _Tp& __construct_alt(__alt<_Ip, _Tp>& __a, _Args&&... __args) { ::new ((void*)_VSTD::addressof(__a)) __alt<_Ip, _Tp>(in_place, _VSTD::forward<_Args>(__args)...); return __a.__value; } template inline _LIBCPP_INLINE_VISIBILITY static void __generic_construct(__constructor& __lhs, _Rhs&& __rhs) { __lhs.__destroy(); if (!__rhs.valueless_by_exception()) { __visitation::__base::__visit_alt_at( __rhs.index(), [](auto& __lhs_alt, auto&& __rhs_alt) { __construct_alt( __lhs_alt, _VSTD::forward(__rhs_alt).__value); }, __lhs, _VSTD::forward<_Rhs>(__rhs)); __lhs.__index = __rhs.index(); } } }; template class _LIBCPP_TEMPLATE_VIS __move_constructor; #define _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait, \ move_constructor) \ template \ class _LIBCPP_TEMPLATE_VIS __move_constructor<__traits<_Types...>, \ move_constructible_trait> \ : public __constructor<__traits<_Types...>> { \ using __base_type = __constructor<__traits<_Types...>>; \ \ public: \ using __base_type::__base_type; \ using __base_type::operator=; \ \ __move_constructor(const __move_constructor&) = default; \ move_constructor \ ~__move_constructor() = default; \ __move_constructor& operator=(const __move_constructor&) = default; \ __move_constructor& operator=(__move_constructor&&) = default; \ } _LIBCPP_VARIANT_MOVE_CONSTRUCTOR( _Trait::_TriviallyAvailable, __move_constructor(__move_constructor&& __that) = default;); _LIBCPP_VARIANT_MOVE_CONSTRUCTOR( _Trait::_Available, __move_constructor(__move_constructor&& __that) noexcept( __all...>::value) : __move_constructor(__valueless_t{}) { this->__generic_construct(*this, _VSTD::move(__that)); }); _LIBCPP_VARIANT_MOVE_CONSTRUCTOR( _Trait::_Unavailable, __move_constructor(__move_constructor&&) = delete;); #undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR template class _LIBCPP_TEMPLATE_VIS __copy_constructor; #define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait, \ copy_constructor) \ template \ class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>, \ copy_constructible_trait> \ : public __move_constructor<__traits<_Types...>> { \ using __base_type = __move_constructor<__traits<_Types...>>; \ \ public: \ using __base_type::__base_type; \ using __base_type::operator=; \ \ copy_constructor \ __copy_constructor(__copy_constructor&&) = default; \ ~__copy_constructor() = default; \ __copy_constructor& operator=(const __copy_constructor&) = default; \ __copy_constructor& operator=(__copy_constructor&&) = default; \ } _LIBCPP_VARIANT_COPY_CONSTRUCTOR( _Trait::_TriviallyAvailable, __copy_constructor(const __copy_constructor& __that) = default;); _LIBCPP_VARIANT_COPY_CONSTRUCTOR( _Trait::_Available, __copy_constructor(const __copy_constructor& __that) : __copy_constructor(__valueless_t{}) { this->__generic_construct(*this, __that); }); _LIBCPP_VARIANT_COPY_CONSTRUCTOR( _Trait::_Unavailable, __copy_constructor(const __copy_constructor&) = delete;); #undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR template class _LIBCPP_TEMPLATE_VIS __assignment : public __copy_constructor<_Traits> { using __base_type = __copy_constructor<_Traits>; public: using __base_type::__base_type; using __base_type::operator=; template inline _LIBCPP_INLINE_VISIBILITY auto& __emplace(_Args&&... __args) { this->__destroy(); auto& __res = this->__construct_alt(__access::__base::__get_alt<_Ip>(*this), _VSTD::forward<_Args>(__args)...); this->__index = _Ip; return __res; } protected: template inline _LIBCPP_INLINE_VISIBILITY void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) { if (this->index() == _Ip) { __a.__value = _VSTD::forward<_Arg>(__arg); } else { struct { void operator()(true_type) const { __this->__emplace<_Ip>(_VSTD::forward<_Arg>(__arg)); } void operator()(false_type) const { __this->__emplace<_Ip>(_Tp(_VSTD::forward<_Arg>(__arg))); } __assignment* __this; _Arg&& __arg; } __impl{this, _VSTD::forward<_Arg>(__arg)}; __impl(bool_constant || !is_nothrow_move_constructible_v<_Tp>>{}); } } template inline _LIBCPP_INLINE_VISIBILITY void __generic_assign(_That&& __that) { if (this->valueless_by_exception() && __that.valueless_by_exception()) { // do nothing. } else if (__that.valueless_by_exception()) { this->__destroy(); } else { __visitation::__base::__visit_alt_at( __that.index(), [this](auto& __this_alt, auto&& __that_alt) { this->__assign_alt( __this_alt, _VSTD::forward(__that_alt).__value); }, *this, _VSTD::forward<_That>(__that)); } } }; template class _LIBCPP_TEMPLATE_VIS __move_assignment; #define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait, \ move_assignment) \ template \ class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>, \ move_assignable_trait> \ : public __assignment<__traits<_Types...>> { \ using __base_type = __assignment<__traits<_Types...>>; \ \ public: \ using __base_type::__base_type; \ using __base_type::operator=; \ \ __move_assignment(const __move_assignment&) = default; \ __move_assignment(__move_assignment&&) = default; \ ~__move_assignment() = default; \ __move_assignment& operator=(const __move_assignment&) = default; \ move_assignment \ } _LIBCPP_VARIANT_MOVE_ASSIGNMENT( _Trait::_TriviallyAvailable, __move_assignment& operator=(__move_assignment&& __that) = default;); _LIBCPP_VARIANT_MOVE_ASSIGNMENT( _Trait::_Available, __move_assignment& operator=(__move_assignment&& __that) noexcept( __all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_move_assignable_v<_Types>)...>::value) { this->__generic_assign(_VSTD::move(__that)); return *this; }); _LIBCPP_VARIANT_MOVE_ASSIGNMENT( _Trait::_Unavailable, __move_assignment& operator=(__move_assignment&&) = delete;); #undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT template class _LIBCPP_TEMPLATE_VIS __copy_assignment; #define _LIBCPP_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait, \ copy_assignment) \ template \ class _LIBCPP_TEMPLATE_VIS __copy_assignment<__traits<_Types...>, \ copy_assignable_trait> \ : public __move_assignment<__traits<_Types...>> { \ using __base_type = __move_assignment<__traits<_Types...>>; \ \ public: \ using __base_type::__base_type; \ using __base_type::operator=; \ \ __copy_assignment(const __copy_assignment&) = default; \ __copy_assignment(__copy_assignment&&) = default; \ ~__copy_assignment() = default; \ copy_assignment \ __copy_assignment& operator=(__copy_assignment&&) = default; \ } _LIBCPP_VARIANT_COPY_ASSIGNMENT( _Trait::_TriviallyAvailable, __copy_assignment& operator=(const __copy_assignment& __that) = default;); _LIBCPP_VARIANT_COPY_ASSIGNMENT( _Trait::_Available, __copy_assignment& operator=(const __copy_assignment& __that) { this->__generic_assign(__that); return *this; }); _LIBCPP_VARIANT_COPY_ASSIGNMENT( _Trait::_Unavailable, __copy_assignment& operator=(const __copy_assignment&) = delete;); #undef _LIBCPP_VARIANT_COPY_ASSIGNMENT template class _LIBCPP_TEMPLATE_VIS __impl : public __copy_assignment<__traits<_Types...>> { using __base_type = __copy_assignment<__traits<_Types...>>; public: using __base_type::__base_type; using __base_type::operator=; template inline _LIBCPP_INLINE_VISIBILITY void __assign(_Arg&& __arg) { this->__assign_alt(__access::__base::__get_alt<_Ip>(*this), _VSTD::forward<_Arg>(__arg)); } inline _LIBCPP_INLINE_VISIBILITY void __swap(__impl& __that) { if (this->valueless_by_exception() && __that.valueless_by_exception()) { // do nothing. } else if (this->index() == __that.index()) { __visitation::__base::__visit_alt_at( this->index(), [](auto& __this_alt, auto& __that_alt) { using _VSTD::swap; swap(__this_alt.__value, __that_alt.__value); }, *this, __that); } else { __impl* __lhs = this; __impl* __rhs = _VSTD::addressof(__that); if (__lhs->__move_nothrow() && !__rhs->__move_nothrow()) { _VSTD::swap(__lhs, __rhs); } __impl __tmp(_VSTD::move(*__rhs)); #ifndef _LIBCPP_NO_EXCEPTIONS if constexpr (__all...>::value) { this->__generic_construct(*__rhs, _VSTD::move(*__lhs)); } else { // EXTENSION: When the move construction of `__lhs` into `__rhs` throws // and `__tmp` is nothrow move constructible then we move `__tmp` back // into `__rhs` and provide the strong exception safety guarantee. try { this->__generic_construct(*__rhs, _VSTD::move(*__lhs)); } catch (...) { if (__tmp.__move_nothrow()) { this->__generic_construct(*__rhs, _VSTD::move(__tmp)); } throw; } } #else // this isn't consolidated with the `if constexpr` branch above due to // `throw` being ill-formed with exceptions disabled even when discarded. this->__generic_construct(*__rhs, _VSTD::move(*__lhs)); #endif this->__generic_construct(*__lhs, _VSTD::move(__tmp)); } } private: inline _LIBCPP_INLINE_VISIBILITY bool __move_nothrow() const { constexpr bool __results[] = {is_nothrow_move_constructible_v<_Types>...}; return this->valueless_by_exception() || __results[this->index()]; } }; struct __no_narrowing_check { template using _Apply = __identity<_Dest>; }; struct __narrowing_check { template static auto __test_impl(_Dest (&&)[1]) -> __identity<_Dest>; template using _Apply _LIBCPP_NODEBUG_TYPE = decltype(__test_impl<_Dest>({std::declval<_Source>()})); }; template using __check_for_narrowing _LIBCPP_NODEBUG_TYPE = typename _If< #ifdef _LIBCPP_ENABLE_NARROWING_CONVERSIONS_IN_VARIANT false && #endif is_arithmetic<_Dest>::value, __narrowing_check, __no_narrowing_check >::template _Apply<_Dest, _Source>; template struct __overload { template auto operator()(_Tp, _Up&&) const -> __check_for_narrowing<_Tp, _Up>; }; template struct __overload_bool { template > auto operator()(bool, _Up&&) const -> enable_if_t, __identity<_Tp>>; }; template struct __overload : __overload_bool {}; template struct __overload : __overload_bool {}; template struct __overload : __overload_bool {}; template struct __overload : __overload_bool {}; template struct __all_overloads : _Bases... { void operator()() const; using _Bases::operator()...; }; template struct __make_overloads_imp; template struct __make_overloads_imp<__tuple_indices<_Idx...> > { template using _Apply _LIBCPP_NODEBUG_TYPE = __all_overloads<__overload<_Types, _Idx>...>; }; template using _MakeOverloads _LIBCPP_NODEBUG_TYPE = typename __make_overloads_imp< __make_indices_imp >::template _Apply<_Types...>; template using __best_match_t = typename invoke_result_t<_MakeOverloads<_Types...>, _Tp, _Tp>::type; } // __variant_detail template class _LIBCPP_TEMPLATE_VIS variant : private __sfinae_ctor_base< __all...>::value, __all...>::value>, private __sfinae_assign_base< __all<(is_copy_constructible_v<_Types> && is_copy_assignable_v<_Types>)...>::value, __all<(is_move_constructible_v<_Types> && is_move_assignable_v<_Types>)...>::value> { static_assert(0 < sizeof...(_Types), "variant must consist of at least one alternative."); static_assert(__all...>::value, "variant can not have an array type as an alternative."); static_assert(__all...>::value, "variant can not have a reference type as an alternative."); static_assert(__all...>::value, "variant can not have a void type as an alternative."); using __first_type = variant_alternative_t<0, variant>; public: template , _Dummy>::value, int> = 0> inline _LIBCPP_INLINE_VISIBILITY constexpr variant() noexcept(is_nothrow_default_constructible_v<__first_type>) : __impl(in_place_index<0>) {} variant(const variant&) = default; variant(variant&&) = default; template < class _Arg, enable_if_t, variant>, int> = 0, enable_if_t>::value, int> = 0, enable_if_t>::value, int> = 0, class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>, size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, enable_if_t, int> = 0> inline _LIBCPP_INLINE_VISIBILITY constexpr variant(_Arg&& __arg) noexcept( is_nothrow_constructible_v<_Tp, _Arg>) : __impl(in_place_index<_Ip>, _VSTD::forward<_Arg>(__arg)) {} template , class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, enable_if_t, int> = 0> inline _LIBCPP_INLINE_VISIBILITY explicit constexpr variant( in_place_index_t<_Ip>, _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, _Args...>) : __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {} template < size_t _Ip, class _Up, class... _Args, enable_if_t<(_Ip < sizeof...(_Types)), int> = 0, class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, enable_if_t&, _Args...>, int> = 0> inline _LIBCPP_INLINE_VISIBILITY explicit constexpr variant( in_place_index_t<_Ip>, initializer_list<_Up> __il, _Args&&... __args) noexcept( is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>) : __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {} template < class _Tp, class... _Args, size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, enable_if_t, int> = 0> inline _LIBCPP_INLINE_VISIBILITY explicit constexpr variant(in_place_type_t<_Tp>, _Args&&... __args) noexcept( is_nothrow_constructible_v<_Tp, _Args...>) : __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {} template < class _Tp, class _Up, class... _Args, size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, enable_if_t&, _Args...>, int> = 0> inline _LIBCPP_INLINE_VISIBILITY explicit constexpr variant( in_place_type_t<_Tp>, initializer_list<_Up> __il, _Args&&... __args) noexcept( is_nothrow_constructible_v<_Tp, initializer_list< _Up>&, _Args...>) : __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {} ~variant() = default; variant& operator=(const variant&) = default; variant& operator=(variant&&) = default; template < class _Arg, enable_if_t, variant>, int> = 0, class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>, size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, enable_if_t && is_constructible_v<_Tp, _Arg>, int> = 0> inline _LIBCPP_INLINE_VISIBILITY variant& operator=(_Arg&& __arg) noexcept( is_nothrow_assignable_v<_Tp&, _Arg> && is_nothrow_constructible_v<_Tp, _Arg>) { __impl.template __assign<_Ip>(_VSTD::forward<_Arg>(__arg)); return *this; } template < size_t _Ip, class... _Args, enable_if_t<(_Ip < sizeof...(_Types)), int> = 0, class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, enable_if_t, int> = 0> inline _LIBCPP_INLINE_VISIBILITY _Tp& emplace(_Args&&... __args) { return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...); } template < size_t _Ip, class _Up, class... _Args, enable_if_t<(_Ip < sizeof...(_Types)), int> = 0, class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, enable_if_t&, _Args...>, int> = 0> inline _LIBCPP_INLINE_VISIBILITY _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) { return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...); } template < class _Tp, class... _Args, size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, enable_if_t, int> = 0> inline _LIBCPP_INLINE_VISIBILITY _Tp& emplace(_Args&&... __args) { return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...); } template < class _Tp, class _Up, class... _Args, size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, enable_if_t&, _Args...>, int> = 0> inline _LIBCPP_INLINE_VISIBILITY _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) { return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...); } inline _LIBCPP_INLINE_VISIBILITY constexpr bool valueless_by_exception() const noexcept { return __impl.valueless_by_exception(); } inline _LIBCPP_INLINE_VISIBILITY constexpr size_t index() const noexcept { return __impl.index(); } template < bool _Dummy = true, enable_if_t< __all<( __dependent_type, _Dummy>::value && __dependent_type, _Dummy>::value)...>::value, int> = 0> inline _LIBCPP_INLINE_VISIBILITY void swap(variant& __that) noexcept( __all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_swappable_v<_Types>)...>::value) { __impl.__swap(__that.__impl); } private: __variant_detail::__impl<_Types...> __impl; friend struct __variant_detail::__access::__variant; friend struct __variant_detail::__visitation::__variant; }; template inline _LIBCPP_INLINE_VISIBILITY constexpr bool __holds_alternative(const variant<_Types...>& __v) noexcept { return __v.index() == _Ip; } template inline _LIBCPP_INLINE_VISIBILITY constexpr bool holds_alternative(const variant<_Types...>& __v) noexcept { return __holds_alternative<__find_exactly_one_t<_Tp, _Types...>::value>(__v); } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr auto&& __generic_get(_Vp&& __v) { using __variant_detail::__access::__variant; if (!__holds_alternative<_Ip>(__v)) { __throw_bad_variant_access(); } return __variant::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v)).__value; } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr variant_alternative_t<_Ip, variant<_Types...>>& get( variant<_Types...>& __v) { static_assert(_Ip < sizeof...(_Types)); static_assert(!is_void_v>>); return __generic_get<_Ip>(__v); } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr variant_alternative_t<_Ip, variant<_Types...>>&& get( variant<_Types...>&& __v) { static_assert(_Ip < sizeof...(_Types)); static_assert(!is_void_v>>); return __generic_get<_Ip>(_VSTD::move(__v)); } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const variant_alternative_t<_Ip, variant<_Types...>>& get( const variant<_Types...>& __v) { static_assert(_Ip < sizeof...(_Types)); static_assert(!is_void_v>>); return __generic_get<_Ip>(__v); } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const variant_alternative_t<_Ip, variant<_Types...>>&& get( const variant<_Types...>&& __v) { static_assert(_Ip < sizeof...(_Types)); static_assert(!is_void_v>>); return __generic_get<_Ip>(_VSTD::move(__v)); } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Tp& get(variant<_Types...>& __v) { static_assert(!is_void_v<_Tp>); return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v); } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Tp&& get(variant<_Types...>&& __v) { static_assert(!is_void_v<_Tp>); return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>( _VSTD::move(__v)); } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const _Tp& get(const variant<_Types...>& __v) { static_assert(!is_void_v<_Tp>); return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v); } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const _Tp&& get(const variant<_Types...>&& __v) { static_assert(!is_void_v<_Tp>); return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>( _VSTD::move(__v)); } template inline _LIBCPP_INLINE_VISIBILITY constexpr auto* __generic_get_if(_Vp* __v) noexcept { using __variant_detail::__access::__variant; return __v && __holds_alternative<_Ip>(*__v) ? _VSTD::addressof(__variant::__get_alt<_Ip>(*__v).__value) : nullptr; } template inline _LIBCPP_INLINE_VISIBILITY constexpr add_pointer_t>> get_if(variant<_Types...>* __v) noexcept { static_assert(_Ip < sizeof...(_Types)); static_assert(!is_void_v>>); return __generic_get_if<_Ip>(__v); } template inline _LIBCPP_INLINE_VISIBILITY constexpr add_pointer_t>> get_if(const variant<_Types...>* __v) noexcept { static_assert(_Ip < sizeof...(_Types)); static_assert(!is_void_v>>); return __generic_get_if<_Ip>(__v); } template inline _LIBCPP_INLINE_VISIBILITY constexpr add_pointer_t<_Tp> get_if(variant<_Types...>* __v) noexcept { static_assert(!is_void_v<_Tp>); return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v); } template inline _LIBCPP_INLINE_VISIBILITY constexpr add_pointer_t get_if(const variant<_Types...>* __v) noexcept { static_assert(!is_void_v<_Tp>); return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v); } template struct __convert_to_bool { template _LIBCPP_INLINE_VISIBILITY constexpr bool operator()(_T1 && __t1, _T2&& __t2) const { static_assert(std::is_convertible(__t1), _VSTD::forward<_T2>(__t2))), bool>::value, "the relational operator does not return a type which is implicitly convertible to bool"); return _Operator{}(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2)); } }; template inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator==(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { using __variant_detail::__visitation::__variant; if (__lhs.index() != __rhs.index()) return false; if (__lhs.valueless_by_exception()) return true; return __variant::__visit_value_at(__lhs.index(), __convert_to_bool>{}, __lhs, __rhs); } template inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator!=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { using __variant_detail::__visitation::__variant; if (__lhs.index() != __rhs.index()) return true; if (__lhs.valueless_by_exception()) return false; return __variant::__visit_value_at( __lhs.index(), __convert_to_bool>{}, __lhs, __rhs); } template inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator<(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { using __variant_detail::__visitation::__variant; if (__rhs.valueless_by_exception()) return false; if (__lhs.valueless_by_exception()) return true; if (__lhs.index() < __rhs.index()) return true; if (__lhs.index() > __rhs.index()) return false; return __variant::__visit_value_at(__lhs.index(), __convert_to_bool>{}, __lhs, __rhs); } template inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator>(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { using __variant_detail::__visitation::__variant; if (__lhs.valueless_by_exception()) return false; if (__rhs.valueless_by_exception()) return true; if (__lhs.index() > __rhs.index()) return true; if (__lhs.index() < __rhs.index()) return false; return __variant::__visit_value_at(__lhs.index(), __convert_to_bool>{}, __lhs, __rhs); } template inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator<=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { using __variant_detail::__visitation::__variant; if (__lhs.valueless_by_exception()) return true; if (__rhs.valueless_by_exception()) return false; if (__lhs.index() < __rhs.index()) return true; if (__lhs.index() > __rhs.index()) return false; return __variant::__visit_value_at( __lhs.index(), __convert_to_bool>{}, __lhs, __rhs); } template inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator>=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { using __variant_detail::__visitation::__variant; if (__rhs.valueless_by_exception()) return true; if (__lhs.valueless_by_exception()) return false; if (__lhs.index() > __rhs.index()) return true; if (__lhs.index() < __rhs.index()) return false; return __variant::__visit_value_at( __lhs.index(), __convert_to_bool>{}, __lhs, __rhs); } template inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs) { using __variant_detail::__visitation::__variant; bool __results[] = {__vs.valueless_by_exception()...}; for (bool __result : __results) { if (__result) { __throw_bad_variant_access(); } } return __variant::__visit_value(_VSTD::forward<_Visitor>(__visitor), _VSTD::forward<_Vs>(__vs)...); } struct _LIBCPP_TEMPLATE_VIS monostate {}; inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator<(monostate, monostate) noexcept { return false; } inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator>(monostate, monostate) noexcept { return false; } inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator<=(monostate, monostate) noexcept { return true; } inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator>=(monostate, monostate) noexcept { return true; } inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator==(monostate, monostate) noexcept { return true; } inline _LIBCPP_INLINE_VISIBILITY constexpr bool operator!=(monostate, monostate) noexcept { return false; } template inline _LIBCPP_INLINE_VISIBILITY auto swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs) noexcept(noexcept(__lhs.swap(__rhs))) -> decltype(__lhs.swap(__rhs)) { __lhs.swap(__rhs); } template struct _LIBCPP_TEMPLATE_VIS hash< __enable_hash_helper, remove_const_t<_Types>...>> { using argument_type = variant<_Types...>; using result_type = size_t; inline _LIBCPP_INLINE_VISIBILITY result_type operator()(const argument_type& __v) const { using __variant_detail::__visitation::__variant; size_t __res = __v.valueless_by_exception() ? 299792458 // Random value chosen by the universe upon creation : __variant::__visit_alt( [](const auto& __alt) { using __alt_type = __uncvref_t; using __value_type = remove_const_t< typename __alt_type::__value_type>; return hash<__value_type>{}(__alt.__value); }, __v); return __hash_combine(__res, hash{}(__v.index())); } }; template <> struct _LIBCPP_TEMPLATE_VIS hash { using argument_type = monostate; using result_type = size_t; inline _LIBCPP_INLINE_VISIBILITY result_type operator()(const argument_type&) const _NOEXCEPT { return 66740831; // return a fundamentally attractive random value. } }; #endif // _LIBCPP_STD_VER > 14 _LIBCPP_END_NAMESPACE_STD _LIBCPP_POP_MACROS #endif // _LIBCPP_VARIANT