//===----------------------------------------------------------------------===//
//
// 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
// <utility>
// template <class T1, class T2> struct pair
// template <class U, class V>
// constexpr explicit(see below) pair(pair<U, V>&& p);
#include <utility>
#include <memory>
#include <cassert>
#include "archetypes.h"
#include "test_convertible.h"
#include "test_macros.h"
using namespace ImplicitTypes; // Get implicitly archetypes
template <class T1, class U1,
bool CanCopy = true, bool CanConvert = CanCopy>
void test_pair_rv()
{
using P1 = std::pair<T1, int>;
using P2 = std::pair<int, T1>;
using UP1 = std::pair<U1, int>&&;
using UP2 = std::pair<int, U1>&&;
static_assert(std::is_constructible<P1, UP1>::value == CanCopy, "");
static_assert(test_convertible<P1, UP1>() == CanConvert, "");
static_assert(std::is_constructible<P2, UP2>::value == CanCopy, "");
static_assert(test_convertible<P2, UP2>() == CanConvert, "");
}
struct Base
{
virtual ~Base() {}
};
struct Derived
: public Base
{
};
template <class T, class U>
struct DPair : public std::pair<T, U> {
using Base = std::pair<T, U>;
using Base::Base;
};
struct ExplicitT {
constexpr explicit ExplicitT(int x) : value(x) {}
int value;
};
struct ImplicitT {
constexpr ImplicitT(int x) : value(x) {}
int value;
};
struct NotCopyOrMoveConstructible {
NotCopyOrMoveConstructible() = default;
NotCopyOrMoveConstructible(NotCopyOrMoveConstructible const&) = delete;
NotCopyOrMoveConstructible(NotCopyOrMoveConstructible&&) = delete;
};
struct NonCopyConstructible {
NonCopyConstructible(NonCopyConstructible const&) = delete;
NonCopyConstructible(NonCopyConstructible&&) = default;
};
int main(int, char**)
{
{
typedef std::pair<std::unique_ptr<Derived>, int> P1;
typedef std::pair<std::unique_ptr<Base>, long> P2;
P1 p1(std::unique_ptr<Derived>(), 4);
P2 p2 = std::move(p1);
assert(p2.first == nullptr);
assert(p2.second == 4);
}
{
// We allow derived types to use this constructor
using P1 = DPair<long, long>;
using P2 = std::pair<int, int>;
P1 p1(42, 101);
P2 p2(std::move(p1));
assert(p2.first == 42);
assert(p2.second == 101);
}
{
test_pair_rv<AllCtors, AllCtors>();
test_pair_rv<AllCtors, AllCtors&>();
test_pair_rv<AllCtors, AllCtors&&>();
test_pair_rv<AllCtors, const AllCtors&>();
test_pair_rv<AllCtors, const AllCtors&&>();
test_pair_rv<ExplicitTypes::AllCtors, ExplicitTypes::AllCtors>();
test_pair_rv<ExplicitTypes::AllCtors, ExplicitTypes::AllCtors&, true, false>();
test_pair_rv<ExplicitTypes::AllCtors, ExplicitTypes::AllCtors&&, true, false>();
test_pair_rv<ExplicitTypes::AllCtors, const ExplicitTypes::AllCtors&, true, false>();
test_pair_rv<ExplicitTypes::AllCtors, const ExplicitTypes::AllCtors&&, true, false>();
test_pair_rv<MoveOnly, MoveOnly>();
test_pair_rv<MoveOnly, MoveOnly&, false>();
test_pair_rv<MoveOnly, MoveOnly&&>();
test_pair_rv<ExplicitTypes::MoveOnly, ExplicitTypes::MoveOnly>(); // copy construction
test_pair_rv<ExplicitTypes::MoveOnly, ExplicitTypes::MoveOnly&, false>();
test_pair_rv<ExplicitTypes::MoveOnly, ExplicitTypes::MoveOnly&&, true, false>();
test_pair_rv<CopyOnly, CopyOnly>();
test_pair_rv<CopyOnly, CopyOnly&>();
test_pair_rv<CopyOnly, CopyOnly&&>();
/* For ExplicitTypes::CopyOnly, two of the viable candidates for initializing from a non-const xvalue are:
* pair(const pair&); // (defaulted copy constructor)
* template<class U1, class U2> explicit pair(const pair<U1, U2>&&); [U1 = ExplicitTypes::CopyOnly, U2 = int]
*
* This results in diverging behavior for test_convertible which uses copy-list-initialization.
* Prior to CWG2137, this would have selected the first (non-explicit) ctor as explicit ctors
* would not be considered. Afterwards, it should select the second since it is a better match,
* and then failed because it is explicit.
*
* This may change with future defect reports, and some compilers only have partial support
* for CWG2137, so use std::is_convertible directly to avoid a copy-list-initialization
*/
{
using P1 = std::pair<ExplicitTypes::CopyOnly, int>;
using P2 = std::pair<int, ExplicitTypes::CopyOnly>;
using UP1 = std::pair<ExplicitTypes::CopyOnly, int>&&;
using UP2 = std::pair<int, ExplicitTypes::CopyOnly>&&;
static_assert(std::is_constructible<P1, UP1>::value, "");
static_assert(std::is_convertible<P1, UP1>::value, "");
static_assert(std::is_constructible<P2, UP2>::value, "");
static_assert(std::is_convertible<P2, UP2>::value, "");
}
test_pair_rv<ExplicitTypes::CopyOnly, ExplicitTypes::CopyOnly&, true, false>();
test_pair_rv<ExplicitTypes::CopyOnly, ExplicitTypes::CopyOnly&&, true, false>();
test_pair_rv<NonCopyable, NonCopyable, false>();
test_pair_rv<NonCopyable, NonCopyable&, false>();
test_pair_rv<NonCopyable, NonCopyable&&, false>();
test_pair_rv<NonCopyable, const NonCopyable&, false>();
test_pair_rv<NonCopyable, const NonCopyable&&, false>();
}
{ // Test construction of references
test_pair_rv<NonCopyable&, NonCopyable&>();
test_pair_rv<NonCopyable&, NonCopyable&&>();
test_pair_rv<NonCopyable&, NonCopyable const&, false>();
test_pair_rv<NonCopyable const&, NonCopyable&&>();
test_pair_rv<NonCopyable&&, NonCopyable&&>();
test_pair_rv<ConvertingType&, int, false>();
test_pair_rv<ExplicitTypes::ConvertingType&, int, false>();
// Unfortunately the below conversions are allowed and create dangling
// references.
//test_pair_rv<ConvertingType&&, int>();
//test_pair_rv<ConvertingType const&, int>();
//test_pair_rv<ConvertingType const&&, int>();
// But these are not because the converting constructor is explicit.
test_pair_rv<ExplicitTypes::ConvertingType&&, int, false>();
test_pair_rv<ExplicitTypes::ConvertingType const&, int, false>();
test_pair_rv<ExplicitTypes::ConvertingType const&&, int, false>();
}
{
test_pair_rv<AllCtors, int, false>();
test_pair_rv<ExplicitTypes::AllCtors, int, false>();
test_pair_rv<ConvertingType, int>();
test_pair_rv<ExplicitTypes::ConvertingType, int, true, false>();
test_pair_rv<ConvertingType, int>();
test_pair_rv<ConvertingType, ConvertingType>();
test_pair_rv<ConvertingType, ConvertingType const&>();
test_pair_rv<ConvertingType, ConvertingType&>();
test_pair_rv<ConvertingType, ConvertingType&&>();
test_pair_rv<ExplicitTypes::ConvertingType, int, true, false>();
test_pair_rv<ExplicitTypes::ConvertingType, int&, true, false>();
test_pair_rv<ExplicitTypes::ConvertingType, const int&, true, false>();
test_pair_rv<ExplicitTypes::ConvertingType, int&&, true, false>();
test_pair_rv<ExplicitTypes::ConvertingType, const int&&, true, false>();
test_pair_rv<ExplicitTypes::ConvertingType, ExplicitTypes::ConvertingType>();
test_pair_rv<ExplicitTypes::ConvertingType, ExplicitTypes::ConvertingType const&, true, false>();
test_pair_rv<ExplicitTypes::ConvertingType, ExplicitTypes::ConvertingType&, true, false>();
test_pair_rv<ExplicitTypes::ConvertingType, ExplicitTypes::ConvertingType&&, true, false>();
}
{
// When constructing a pair containing a reference, we only bind the
// reference, so it doesn't matter whether the type is or isn't
// copy/move constructible.
{
using P1 = std::pair<NotCopyOrMoveConstructible&, long>;
using P2 = std::pair<NotCopyOrMoveConstructible&, int>;
static_assert(std::is_constructible<P1, P2&&>::value, "");
NotCopyOrMoveConstructible obj;
P2 p2{obj, 3};
P1 p1(std::move(p2));
assert(&p1.first == &obj);
assert(&p2.first == &obj);
}
{
using P1 = std::pair<NotCopyOrMoveConstructible&&, long>;
using P2 = std::pair<NotCopyOrMoveConstructible&&, int>;
static_assert(std::is_constructible<P1, P2&&>::value, "");
NotCopyOrMoveConstructible obj;
P2 p2{std::move(obj), 3};
P1 p1(std::move(p2));
assert(&p1.first == &obj);
assert(&p2.first == &obj);
}
}
{
// Make sure we can't move-construct from a pair containing a reference
// if that type isn't copy-constructible (since otherwise we'd be stealing
// the object through the reference).
using P1 = std::pair<NonCopyConstructible, long>;
using P2 = std::pair<NonCopyConstructible&, int>;
static_assert(!std::is_constructible<P1, P2&&>::value, "");
}
#if TEST_STD_VER > 11
{ // explicit constexpr test
constexpr std::pair<int, int> p1(42, 43);
constexpr std::pair<ExplicitT, ExplicitT> p2(std::move(p1));
static_assert(p2.first.value == 42, "");
static_assert(p2.second.value == 43, "");
}
{ // implicit constexpr test
constexpr std::pair<int, int> p1(42, 43);
constexpr std::pair<ImplicitT, ImplicitT> p2 = std::move(p1);
static_assert(p2.first.value == 42, "");
static_assert(p2.second.value == 43, "");
}
#endif
return 0;
}
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