[libc++] Make constexpr std::variant. Implement P2231R1
#83335
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@llvm/pr-subscribers-libcxx Author: Hui (huixie90) ChangesPatch is 128.29 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/83335.diff 12 Files Affected:
diff --git a/libcxx/include/variant b/libcxx/include/variant
index 6063739e52c86b..2a583f6dbd2006 100644
--- a/libcxx/include/variant
+++ b/libcxx/include/variant
@@ -42,26 +42,27 @@ namespace std {
in_place_index_t<I>, initializer_list<U>, Args&&...);
// 20.7.2.2, destructor
- ~variant();
+ constexpr ~variant(); // constexpr since c++20
// 20.7.2.3, assignment
constexpr variant& operator=(const variant&);
constexpr variant& operator=(variant&&) noexcept(see below);
- template <class T> variant& operator=(T&&) noexcept(see below);
+ template <class T>
+ constexpr variant& operator=(T&&) noexcept(see below); // constexpr since c++20
// 20.7.2.4, modifiers
template <class T, class... Args>
- T& emplace(Args&&...);
+ constexpr T& emplace(Args&&...); // constexpr since c++20
template <class T, class U, class... Args>
- T& emplace(initializer_list<U>, Args&&...);
+ constexpr T& emplace(initializer_list<U>, Args&&...); // constexpr since c++20
template <size_t I, class... Args>
- variant_alternative_t<I, variant>& emplace(Args&&...);
+ constexpr variant_alternative_t<I, variant>& emplace(Args&&...); // constexpr since c++20
template <size_t I, class U, class... Args>
- variant_alternative_t<I, variant>& emplace(initializer_list<U>, Args&&...);
+ constexpr variant_alternative_t<I, variant>& emplace(initializer_list<U>, Args&&...); // constexpr since c++20
// 20.7.2.5, value status
constexpr bool valueless_by_exception() const noexcept;
@@ -222,6 +223,7 @@ namespace std {
#include <__functional/operations.h>
#include <__functional/unary_function.h>
#include <__memory/addressof.h>
+#include <__memory/construct_at.h>
#include <__type_traits/add_const.h>
#include <__type_traits/add_cv.h>
#include <__type_traits/add_pointer.h>
@@ -655,7 +657,8 @@ private:
template <size_t _Index, class _Tp>
struct _LIBCPP_TEMPLATE_VIS __alt {
- using __value_type = _Tp;
+ using __value_type = _Tp;
+ static constexpr size_t __index = _Index;
template <class... _Args>
_LIBCPP_HIDE_FROM_ABI explicit constexpr __alt(in_place_t, _Args&&... __args)
@@ -687,7 +690,7 @@ union _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {};
__union(const __union&) = default; \
__union(__union&&) = default; \
\
- destructor \
+ _LIBCPP_HIDE_FROM_ABI destructor \
\
__union& \
operator=(const __union&) = default; \
@@ -701,9 +704,9 @@ union _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {};
friend struct __access::__union; \
}
-_LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable, ~__union() = default;);
-_LIBCPP_VARIANT_UNION(_Trait::_Available, ~__union(){});
-_LIBCPP_VARIANT_UNION(_Trait::_Unavailable, ~__union() = delete;);
+_LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable, _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = default;);
+_LIBCPP_VARIANT_UNION(_Trait::_Available, _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union(){});
+_LIBCPP_VARIANT_UNION(_Trait::_Unavailable, _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = delete;);
# undef _LIBCPP_VARIANT_UNION
@@ -757,23 +760,23 @@ class _LIBCPP_TEMPLATE_VIS __dtor;
using __base_type::__base_type; \
using __base_type::operator=; \
\
- __dtor(const __dtor&) = default; \
- __dtor(__dtor&&) = default; \
- destructor __dtor& operator=(const __dtor&) = default; \
- __dtor& operator=(__dtor&&) = default; \
+ __dtor(const __dtor&) = default; \
+ __dtor(__dtor&&) = default; \
+ _LIBCPP_HIDE_FROM_ABI destructor __dtor& operator=(const __dtor&) = default; \
+ __dtor& operator=(__dtor&&) = default; \
\
protected: \
inline _LIBCPP_HIDE_FROM_ABI destroy \
}
_LIBCPP_VARIANT_DESTRUCTOR(
- _Trait::_TriviallyAvailable, ~__dtor() = default;
- , void __destroy() noexcept { this->__index = __variant_npos<__index_t>; });
+ _Trait::_TriviallyAvailable, _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = default;
+ , _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept { this->__index = __variant_npos<__index_t>; });
_LIBCPP_VARIANT_DESTRUCTOR(
_Trait::_Available,
- ~__dtor() { __destroy(); },
- void __destroy() noexcept {
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() { __destroy(); },
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept {
if (!this->valueless_by_exception()) {
__visitation::__base::__visit_alt(
[](auto& __alt) noexcept {
@@ -785,7 +788,8 @@ _LIBCPP_VARIANT_DESTRUCTOR(
this->__index = __variant_npos<__index_t>;
});
-_LIBCPP_VARIANT_DESTRUCTOR(_Trait::_Unavailable, ~__dtor() = delete;, void __destroy() noexcept = delete;);
+_LIBCPP_VARIANT_DESTRUCTOR(_Trait::_Unavailable, _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = delete;
+ , _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept = delete;);
# undef _LIBCPP_VARIANT_DESTRUCTOR
@@ -798,23 +802,22 @@ public:
using __base_type::operator=;
protected:
- template <size_t _Ip, class _Tp, class... _Args>
- _LIBCPP_HIDE_FROM_ABI static _Tp& __construct_alt(__alt<_Ip, _Tp>& __a, _Args&&... __args) {
- ::new ((void*)std::addressof(__a)) __alt<_Ip, _Tp>(in_place, std::forward<_Args>(__args)...);
- return __a.__value;
- }
-
template <class _Rhs>
- _LIBCPP_HIDE_FROM_ABI static void __generic_construct(__ctor& __lhs, _Rhs&& __rhs) {
+ _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_construct(__ctor& __lhs, _Rhs&& __rhs) {
__lhs.__destroy();
if (!__rhs.valueless_by_exception()) {
+ // We cannot directly construct at the target __alt because its direct enclosing union is not activated yet.
+ // We will get error if we did:
+ // construction of subobject of member '__tail' of union with active member '__dummy' is not allowed in a constant
+ // expression
auto __rhs_index = __rhs.index();
__visitation::__base::__visit_alt_at(
__rhs_index,
- [](auto& __lhs_alt, auto&& __rhs_alt) {
- __construct_alt(__lhs_alt, std::forward<decltype(__rhs_alt)>(__rhs_alt).__value);
+ [&__lhs](auto&& __rhs_alt) {
+ std::__construct_at(std::addressof(__lhs.__data),
+ in_place_index<__decay_t<decltype(__rhs_alt)>::__index>,
+ std::forward<decltype(__rhs_alt)>(__rhs_alt).__value);
},
- __lhs,
std::forward<_Rhs>(__rhs));
__lhs.__index = __rhs_index;
}
@@ -834,21 +837,24 @@ class _LIBCPP_TEMPLATE_VIS __move_constructor;
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; \
+ __move_constructor(const __move_constructor&) = default; \
+ _LIBCPP_HIDE_FROM_ABI 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::_TriviallyAvailable,
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) = default;);
_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
_Trait::_Available,
- __move_constructor(__move_constructor&& __that) noexcept(__all<is_nothrow_move_constructible_v<_Types>...>::value)
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) noexcept(
+ __all<is_nothrow_move_constructible_v<_Types>...>::value)
: __move_constructor(__valueless_t{}) { this->__generic_construct(*this, std::move(__that)); });
-_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(_Trait::_Unavailable, __move_constructor(__move_constructor&&) = delete;);
+_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(_Trait::_Unavailable,
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&&) = delete;);
# undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR
@@ -865,20 +871,22 @@ class _LIBCPP_TEMPLATE_VIS __copy_constructor;
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_HIDE_FROM_ABI 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::_TriviallyAvailable,
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor& __that) = default;);
_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
- _Trait::_Available, __copy_constructor(const __copy_constructor& __that)
+ _Trait::_Available, _LIBCPP_CONSTEXPR_SINCE_CXX20 __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;);
+_LIBCPP_VARIANT_COPY_CONSTRUCTOR(_Trait::_Unavailable,
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor&) = delete;);
# undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR
@@ -891,22 +899,24 @@ public:
using __base_type::operator=;
template <size_t _Ip, class... _Args>
- _LIBCPP_HIDE_FROM_ABI auto& __emplace(_Args&&... __args) {
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto& __emplace(_Args&&... __args) {
this->__destroy();
- auto& __res = this->__construct_alt(__access::__base::__get_alt<_Ip>(*this), std::forward<_Args>(__args)...);
+ std::__construct_at(std::addressof(this->__data), in_place_index<_Ip>, std::forward<_Args>(__args)...);
this->__index = _Ip;
- return __res;
+ return __access::__base::__get_alt<_Ip>(*this).__value;
}
protected:
template <size_t _Ip, class _Tp, class _Arg>
- _LIBCPP_HIDE_FROM_ABI void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) {
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) {
if (this->index() == _Ip) {
__a.__value = std::forward<_Arg>(__arg);
} else {
struct {
- _LIBCPP_HIDE_FROM_ABI void operator()(true_type) const { __this->__emplace<_Ip>(std::forward<_Arg>(__arg)); }
- _LIBCPP_HIDE_FROM_ABI void operator()(false_type) const {
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(true_type) const {
+ __this->__emplace<_Ip>(std::forward<_Arg>(__arg));
+ }
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(false_type) const {
__this->__emplace<_Ip>(_Tp(std::forward<_Arg>(__arg)));
}
__assignment* __this;
@@ -917,7 +927,7 @@ protected:
}
template <class _That>
- _LIBCPP_HIDE_FROM_ABI void __generic_assign(_That&& __that) {
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_assign(_That&& __that) {
if (this->valueless_by_exception() && __that.valueless_by_exception()) {
// do nothing.
} else if (__that.valueless_by_exception()) {
@@ -951,22 +961,24 @@ class _LIBCPP_TEMPLATE_VIS __move_assignment;
__move_assignment(__move_assignment&&) = default; \
~__move_assignment() = default; \
__move_assignment& operator=(const __move_assignment&) = default; \
- move_assignment \
+ _LIBCPP_HIDE_FROM_ABI move_assignment \
}
-_LIBCPP_VARIANT_MOVE_ASSIGNMENT(_Trait::_TriviallyAvailable,
- __move_assignment& operator=(__move_assignment&& __that) = default;);
+_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
+ _Trait::_TriviallyAvailable,
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=(__move_assignment&& __that) = default;);
_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
_Trait::_Available,
- __move_assignment&
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment&
operator=(__move_assignment&& __that) noexcept(
__all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_move_assignable_v<_Types>)...>::value) {
this->__generic_assign(std::move(__that));
return *this;
});
-_LIBCPP_VARIANT_MOVE_ASSIGNMENT(_Trait::_Unavailable, __move_assignment& operator=(__move_assignment&&) = delete;);
+_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
+ _Trait::_Unavailable, _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=(__move_assignment&&) = delete;);
# undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT
@@ -983,22 +995,25 @@ class _LIBCPP_TEMPLATE_VIS __copy_assignment;
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; \
+ __copy_assignment(const __copy_assignment&) = default; \
+ __copy_assignment(__copy_assignment&&) = default; \
+ ~__copy_assignment() = default; \
+ _LIBCPP_HIDE_FROM_ABI 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::_TriviallyAvailable,
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment& operator=(const __copy_assignment& __that) = default;);
_LIBCPP_VARIANT_COPY_ASSIGNMENT(
- _Trait::_Available, __copy_assignment& operator=(const __copy_assignment& __that) {
+ _Trait::_Available, _LIBCPP_CONSTEXPR_SINCE_CXX20 __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;);
+_LIBCPP_VARIANT_COPY_ASSIGNMENT(
+ _Trait::_Unavailable,
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment& operator=(const __copy_assignment&) = delete;);
# undef _LIBCPP_VARIANT_COPY_ASSIGNMENT
@@ -1014,11 +1029,11 @@ public:
_LIBCPP_HIDE_FROM_ABI __impl& operator=(__impl&&) = default;
template <size_t _Ip, class _Arg>
- _LIBCPP_HIDE_FROM_ABI void __assign(_Arg&& __arg) {
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign(_Arg&& __arg) {
this->__assign_alt(__access::__base::__get_alt<_Ip>(*this), std::forward<_Arg>(__arg));
}
- inline _LIBCPP_HIDE_FROM_ABI void __swap(__impl& __that) {
+ inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __swap(__impl& __that) {
if (this->valueless_by_exception() && __that.valueless_by_exception()) {
// do nothing.
} else if (this->index() == __that.index()) {
@@ -1063,7 +1078,7 @@ public:
}
private:
- inline _LIBCPP_HIDE_FROM_ABI bool __move_nothrow() const {
+ constexpr inline _LIBCPP_HIDE_FROM_ABI bool __move_nothrow() const {
constexpr bool __resul...
[truncated]
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You can test this locally with the following command:git-clang-format --diff 50b45b24220ead33cf5cedc49c13e0336297e4eb 0466fbd0bcbcf59f8d7860f4a593fb6c62a34b2d -- libcxx/include/variant libcxx/test/std/utilities/variant/variant.variant/variant.assign/T.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.assign/copy.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.assign/move.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.ctor/copy.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.ctor/default.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.ctor/move.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cppView the diff from clang-format here.diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp
index f98d968f0e..f813b3f0a1 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp
@@ -26,8 +26,8 @@
#include "variant_test_helpers.h"
template <class Var, std::size_t I, class... Args>
-constexpr auto test_emplace_exists_imp(int)
- -> decltype(std::declval<Var>().template emplace<I>(std::declval<Args>()...), true) {
+constexpr auto
+test_emplace_exists_imp(int) -> decltype(std::declval<Var>().template emplace<I>(std::declval<Args>()...), true) {
return true;
}
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp
index 4c635570bd..f14092d145 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp
@@ -36,8 +36,8 @@ struct InitListArg {
};
template <class Var, std::size_t I, class... Args>
-constexpr auto test_emplace_exists_imp(int)
- -> decltype(std::declval<Var>().template emplace<I>(std::declval<Args>()...), true) {
+constexpr auto
+test_emplace_exists_imp(int) -> decltype(std::declval<Var>().template emplace<I>(std::declval<Args>()...), true) {
return true;
}
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp
index c2ed54d8a6..2c91debfa1 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp
@@ -25,8 +25,8 @@
#include "variant_test_helpers.h"
template <class Var, class T, class... Args>
-constexpr auto test_emplace_exists_imp(int)
- -> decltype(std::declval<Var>().template emplace<T>(std::declval<Args>()...), true) {
+constexpr auto
+test_emplace_exists_imp(int) -> decltype(std::declval<Var>().template emplace<T>(std::declval<Args>()...), true) {
return true;
}
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp
index 644f2418b9..a442c7ed5d 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp
@@ -36,8 +36,8 @@ struct InitListArg {
};
template <class Var, class T, class... Args>
-constexpr auto test_emplace_exists_imp(int)
- -> decltype(std::declval<Var>().template emplace<T>(std::declval<Args>()...), true) {
+constexpr auto
+test_emplace_exists_imp(int) -> decltype(std::declval<Var>().template emplace<T>(std::declval<Args>()...), true) {
return true;
}
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp
index db05691c55..7269eae98e 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp
@@ -251,62 +251,63 @@ TEST_CONSTEXPR_CXX20 void test_swap_same_alternative() {
}
}
-void test_swap_same_alternative_throws(){
+void test_swap_same_alternative_throws() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- {using V = std::variant<NothrowTypeWithThrowingSwap, int>;
-int move_called = 0;
-int move_assign_called = 0;
-int swap_called = 0;
-V v1(std::in_place_index<0>, 42, &move_called, &move_assign_called, &swap_called);
-V v2(std::in_place_index<0>, 100, &move_called, &move_assign_called, &swap_called);
-try {
- v1.swap(v2);
- assert(false);
-} catch (int) {
-}
-assert(swap_called == 1);
-assert(move_called == 0);
-assert(move_assign_called == 0);
-assert(std::get<0>(v1).value == 42);
-assert(std::get<0>(v2).value == 100);
-}
+ {
+ using V = std::variant<NothrowTypeWithThrowingSwap, int>;
+ int move_called = 0;
+ int move_assign_called = 0;
+ int swap_called = 0;
+ V v1(std::in_place_index<0>, 42, &move_called, &move_assign_called, &swap_called);
+ V v2(std::in_place_index<0>, 100, &move_called, &move_assign_called, &swap_called);
+ try {
+ v1.swap(v2);
+ assert(false);
+ } catch (int) {
+ }
+ assert(swap_called == 1);
+ assert(move_called == 0);
+ assert(move_assign_called == 0);
+ assert(std::get<0>(v1).value == 42);
+ assert(std::get<0>(v2).value == 100);
+ }
-{
- using V = std::variant<ThrowingMoveCtor, int>;
- int move_called = 0;
- int move_assign_called = 0;
- int swap_called = 0;
- V v1(std::in_place_index<0>, 42, &move_called, &move_assign_called, &swap_called);
- V v2(std::in_place_index<0>, 100, &move_called, &move_assign_called, &swap_called);
- try {
- v1.swap(v2);
- assert(false);
- } catch (int) {
+ {
+ using V = std::variant<ThrowingMoveCtor, int>;
+ int move_called = 0;
+ int move_assign_called = 0;
+ int swap_called = 0;
+ V v1(std::in_place_index<0>, 42, &move_called, &move_assign_called, &swap_called);
+ V v2(std::in_place_index<0>, 100, &move_called, &move_assign_called, &swap_called);
+ try {
+ v1.swap(v2);
+ assert(false);
+ } catch (int) {
+ }
+ assert(move_called == 1); // call threw
+ assert(move_assign_called == 0);
+ assert(swap_called == 0);
+ assert(std::get<0>(v1).value == 42); // throw happened before v1 was moved from
+ assert(std::get<0>(v2).value == 100);
}
- assert(move_called == 1); // call threw
- assert(move_assign_called == 0);
- assert(swap_called == 0);
- assert(std::get<0>(v1).value == 42); // throw happened before v1 was moved from
- assert(std::get<0>(v2).value == 100);
-}
-{
- using V = std::variant<ThrowingMoveAssignNothrowMoveCtor, int>;
- int move_called = 0;
- int move_assign_called = 0;
- int swap_called = 0;
- V v1(std::in_place_index<0>, 42, &move_called, &move_assign_called, &swap_called);
- V v2(std::in_place_index<0>, 100, &move_called, &move_assign_called, &swap_called);
- try {
- v1.swap(v2);
- assert(false);
- } catch (int) {
+ {
+ using V = std::variant<ThrowingMoveAssignNothrowMoveCtor, int>;
+ int move_called = 0;
+ int move_assign_called = 0;
+ int swap_called = 0;
+ V v1(std::in_place_index<0>, 42, &move_called, &move_assign_called, &swap_called);
+ V v2(std::in_place_index<0>, 100, &move_called, &move_assign_called, &swap_called);
+ try {
+ v1.swap(v2);
+ assert(false);
+ } catch (int) {
+ }
+ assert(move_called == 1);
+ assert(move_assign_called == 1); // call threw and didn't complete
+ assert(swap_called == 0);
+ assert(std::get<0>(v1).value == -1); // v1 was moved from
+ assert(std::get<0>(v2).value == 100);
}
- assert(move_called == 1);
- assert(move_assign_called == 1); // call threw and didn't complete
- assert(swap_called == 0);
- assert(std::get<0>(v1).value == -1); // v1 was moved from
- assert(std::get<0>(v2).value == 100);
-}
#endif
}
|
ldionne
approved these changes
Apr 26, 2024
constexpr test for default ctor fix c++17
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ldionne
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May 8, 2024
|
FTM bumping was missing. I'll do the cleanup. |
frederick-vs-ja
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Oct 25, 2024
In C++20 mode, `__cpp_lib_optional` and `__cpp_lib_variant` should be `202106L` due to DR P2231R1. In C++26 mode, `__cpp_lib_variant` should be bumped to `202306L` due to P2637R3. - Clang 16/17 shouldn't get this bumping (as member `visit` requires explicit object parameters), but it's very tricky to make the bumping conditionally enabled. I _hope_ unconditionally bumping in C++26 will be OK for LLVM 20 when the support for Clang 17 is dropped. Related PRs: - https://reviews.llvm.org/D102119 - #83335 - #76447
winner245
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Oct 26, 2024
In C++20 mode, `__cpp_lib_optional` and `__cpp_lib_variant` should be `202106L` due to DR P2231R1. In C++26 mode, `__cpp_lib_variant` should be bumped to `202306L` due to P2637R3. - Clang 16/17 shouldn't get this bumping (as member `visit` requires explicit object parameters), but it's very tricky to make the bumping conditionally enabled. I _hope_ unconditionally bumping in C++26 will be OK for LLVM 20 when the support for Clang 17 is dropped. Related PRs: - https://reviews.llvm.org/D102119 - llvm#83335 - llvm#76447
NoumanAmir657
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Nov 4, 2024
In C++20 mode, `__cpp_lib_optional` and `__cpp_lib_variant` should be `202106L` due to DR P2231R1. In C++26 mode, `__cpp_lib_variant` should be bumped to `202306L` due to P2637R3. - Clang 16/17 shouldn't get this bumping (as member `visit` requires explicit object parameters), but it's very tricky to make the bumping conditionally enabled. I _hope_ unconditionally bumping in C++26 will be OK for LLVM 20 when the support for Clang 17 is dropped. Related PRs: - https://reviews.llvm.org/D102119 - llvm#83335 - llvm#76447
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Fixes #86686