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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;
// template <class T> constexpr variant(T&&) noexcept(see below);
#include <cassert>
#include <string>
#include <type_traits>
#include <variant>
#include <memory>
#include <vector>
#include "test_macros.h"
#include "variant_test_helpers.h"
struct Dummy {
Dummy() = default;
};
struct ThrowsT {
ThrowsT(int) noexcept(false) {}
};
struct NoThrowT {
NoThrowT(int) noexcept(true) {}
};
struct AnyConstructible {
template <typename T>
AnyConstructible(T&&) {}
};
struct NoConstructible {
NoConstructible() = delete;
};
template <class T>
struct RValueConvertibleFrom {
RValueConvertibleFrom(T&&) {}
};
void test_T_ctor_noexcept() {
{
using V = std::variant<Dummy, NoThrowT>;
static_assert(std::is_nothrow_constructible<V, int>::value, "");
}
{
using V = std::variant<Dummy, ThrowsT>;
static_assert(!std::is_nothrow_constructible<V, int>::value, "");
}
}
void test_T_ctor_sfinae() {
{
using V = std::variant<long, long long>;
static_assert(!std::is_constructible<V, int>::value, "ambiguous");
}
{
using V = std::variant<std::string, std::string>;
static_assert(!std::is_constructible<V, const char*>::value, "ambiguous");
}
{
using V = std::variant<std::string, void*>;
static_assert(!std::is_constructible<V, int>::value, "no matching constructor");
}
{
using V = std::variant<std::string, float>;
static_assert(!std::is_constructible<V, int>::value, "no matching constructor");
}
{
using V = std::variant<std::unique_ptr<int>, bool>;
static_assert(!std::is_constructible<V, std::unique_ptr<char>>::value, "no explicit bool in constructor");
struct X {
operator void*();
};
static_assert(!std::is_constructible<V, X>::value, "no boolean conversion in constructor");
static_assert(std::is_constructible<V, std::false_type>::value, "converted to bool in constructor");
}
{
struct X {};
struct Y {
operator X();
};
using V = std::variant<X>;
static_assert(std::is_constructible<V, Y>::value, "regression on user-defined conversions in constructor");
}
{
using V = std::variant<AnyConstructible, NoConstructible>;
static_assert(!std::is_constructible<V, std::in_place_type_t<NoConstructible>>::value, "no matching constructor");
static_assert(!std::is_constructible<V, std::in_place_index_t<1>>::value, "no matching constructor");
}
}
void test_T_ctor_basic() {
{
constexpr std::variant<int> v(42);
static_assert(v.index() == 0, "");
static_assert(std::get<0>(v) == 42, "");
}
{
constexpr std::variant<int, long> v(42l);
static_assert(v.index() == 1, "");
static_assert(std::get<1>(v) == 42, "");
}
{
constexpr std::variant<unsigned, long> v(42);
static_assert(v.index() == 1, "");
static_assert(std::get<1>(v) == 42, "");
}
{
std::variant<std::string, bool const> v = "foo";
assert(v.index() == 0);
assert(std::get<0>(v) == "foo");
}
{
std::variant<bool, std::unique_ptr<int>> v = nullptr;
assert(v.index() == 1);
assert(std::get<1>(v) == nullptr);
}
{
std::variant<bool const, int> v = true;
assert(v.index() == 0);
assert(std::get<0>(v));
}
{
std::variant<RValueConvertibleFrom<int>> v1 = 42;
assert(v1.index() == 0);
int x = 42;
std::variant<RValueConvertibleFrom<int>, AnyConstructible> v2 = x;
assert(v2.index() == 1);
}
}
struct BoomOnAnything {
template <class T>
constexpr BoomOnAnything(T) {
static_assert(!std::is_same<T, T>::value, "");
}
};
void test_no_narrowing_check_for_class_types() {
using V = std::variant<int, BoomOnAnything>;
V v(42);
assert(v.index() == 0);
assert(std::get<0>(v) == 42);
}
struct Bar {};
struct Baz {};
void test_construction_with_repeated_types() {
using V = std::variant<int, Bar, Baz, int, Baz, int, int>;
static_assert(!std::is_constructible<V, int>::value, "");
static_assert(!std::is_constructible<V, Baz>::value, "");
// OK, the selected type appears only once and so it shouldn't
// be affected by the duplicate types.
static_assert(std::is_constructible<V, Bar>::value, "");
}
void test_vector_bool() {
std::vector<bool> vec = {true};
std::variant<bool, int> v = vec[0];
assert(v.index() == 0);
assert(std::get<0>(v) == true);
}
int main(int, char**) {
test_T_ctor_basic();
test_T_ctor_noexcept();
test_T_ctor_sfinae();
test_no_narrowing_check_for_class_types();
test_construction_with_repeated_types();
test_vector_bool();
return 0;
}
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