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//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14
// <variant>
// template <class ...Types> class variant;
// constexpr variant() noexcept(see below);
#include <cassert>
#include <type_traits>
#include <variant>
#include <string>
#include "test_macros.h"
#include "variant_test_helpers.h"
struct NonDefaultConstructible {
constexpr NonDefaultConstructible(int) {}
};
struct NotNoexcept {
NotNoexcept() noexcept(false) {}
};
#ifndef TEST_HAS_NO_EXCEPTIONS
struct DefaultCtorThrows {
DefaultCtorThrows() { throw 42; }
};
#endif
constexpr void test_default_ctor_sfinae() {
{
using V = std::variant<std::monostate, int>;
static_assert(std::is_default_constructible<V>::value, "");
}
{
using V = std::variant<NonDefaultConstructible, int>;
static_assert(!std::is_default_constructible<V>::value, "");
}
}
constexpr void test_default_ctor_noexcept() {
{
using V = std::variant<int>;
static_assert(std::is_nothrow_default_constructible<V>::value, "");
}
{
using V = std::variant<NotNoexcept>;
static_assert(!std::is_nothrow_default_constructible<V>::value, "");
}
}
void test_default_ctor_throws() {
#ifndef TEST_HAS_NO_EXCEPTIONS
using V = std::variant<DefaultCtorThrows, int>;
try {
V v;
assert(false);
} catch (const int& ex) {
assert(ex == 42);
} catch (...) {
assert(false);
}
#endif
}
constexpr void test_default_ctor_basic() {
{
std::variant<int> v;
assert(v.index() == 0);
assert(std::get<0>(v) == 0);
}
{
std::variant<int, long> v;
assert(v.index() == 0);
assert(std::get<0>(v) == 0);
}
{
std::variant<int, NonDefaultConstructible> v;
assert(v.index() == 0);
assert(std::get<0>(v) == 0);
}
{
using V = std::variant<int, long>;
constexpr V v;
static_assert(v.index() == 0, "");
static_assert(std::get<0>(v) == 0, "");
}
{
using V = std::variant<int, long>;
constexpr V v;
static_assert(v.index() == 0, "");
static_assert(std::get<0>(v) == 0, "");
}
{
using V = std::variant<int, NonDefaultConstructible>;
constexpr V v;
static_assert(v.index() == 0, "");
static_assert(std::get<0>(v) == 0, "");
}
}
constexpr void issue_86686() {
#if TEST_STD_VER >= 20
static_assert(std::variant<std::string>{}.index() == 0);
#endif
}
constexpr bool test() {
test_default_ctor_basic();
test_default_ctor_sfinae();
test_default_ctor_noexcept();
issue_86686();
return true;
}
int main(int, char**) {
test();
test_default_ctor_throws();
static_assert(test());
return 0;
}
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