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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
// <utility>
// template <class T1, class T2> struct pair
// pair& operator=(pair&& p);
#include <utility>
#include <memory>
#include <cassert>
#include "test_macros.h"
#include "archetypes.h"
struct CountAssign {
int copied = 0;
int moved = 0;
TEST_CONSTEXPR_CXX20 CountAssign() = default;
TEST_CONSTEXPR_CXX20 CountAssign& operator=(CountAssign const&) {
++copied;
return *this;
}
TEST_CONSTEXPR_CXX20 CountAssign& operator=(CountAssign&&) {
++moved;
return *this;
}
};
struct NotAssignable {
NotAssignable& operator=(NotAssignable const&) = delete;
NotAssignable& operator=(NotAssignable&&) = delete;
};
struct MoveAssignable {
MoveAssignable& operator=(MoveAssignable const&) = delete;
MoveAssignable& operator=(MoveAssignable&&) = default;
};
struct CopyAssignable {
CopyAssignable& operator=(CopyAssignable const&) = default;
CopyAssignable& operator=(CopyAssignable&&) = delete;
};
TEST_CONSTEXPR_CXX20 bool test() {
{
typedef std::pair<ConstexprTestTypes::MoveOnly, int> P;
P p1(3, 4);
P p2;
p2 = std::move(p1);
assert(p2.first.value == 3);
assert(p2.second == 4);
}
{
using P = std::pair<int&, int&&>;
int x = 42;
int y = 101;
int x2 = -1;
int y2 = 300;
P p1(x, std::move(y));
P p2(x2, std::move(y2));
p1 = std::move(p2);
assert(p1.first == x2);
assert(p1.second == y2);
}
{
using P = std::pair<int, ConstexprTestTypes::DefaultOnly>;
static_assert(!std::is_move_assignable<P>::value, "");
}
{
// The move decays to the copy constructor
using P = std::pair<CountAssign, ConstexprTestTypes::CopyOnly>;
static_assert(std::is_move_assignable<P>::value, "");
P p;
P p2;
p = std::move(p2);
assert(p.first.moved == 0);
assert(p.first.copied == 1);
assert(p2.first.moved == 0);
assert(p2.first.copied == 0);
}
{
using P = std::pair<CountAssign, ConstexprTestTypes::MoveOnly>;
static_assert(std::is_move_assignable<P>::value, "");
P p;
P p2;
p = std::move(p2);
assert(p.first.moved == 1);
assert(p.first.copied == 0);
assert(p2.first.moved == 0);
assert(p2.first.copied == 0);
}
{
using P1 = std::pair<int, NotAssignable>;
using P2 = std::pair<NotAssignable, int>;
using P3 = std::pair<NotAssignable, NotAssignable>;
static_assert(!std::is_move_assignable<P1>::value, "");
static_assert(!std::is_move_assignable<P2>::value, "");
static_assert(!std::is_move_assignable<P3>::value, "");
}
{
// We assign through the reference and don't move out of the incoming ref,
// so this doesn't work (but would if the type were CopyAssignable).
using P1 = std::pair<MoveAssignable&, int>;
static_assert(!std::is_move_assignable<P1>::value, "");
// ... works if it's CopyAssignable
using P2 = std::pair<CopyAssignable&, int>;
static_assert(std::is_move_assignable<P2>::value, "");
// For rvalue-references, we can move-assign if the type is MoveAssignable
// or CopyAssignable (since in the worst case the move will decay into a copy).
using P3 = std::pair<MoveAssignable&&, int>;
using P4 = std::pair<CopyAssignable&&, int>;
static_assert(std::is_move_assignable<P3>::value, "");
static_assert(std::is_move_assignable<P4>::value, "");
// In all cases, we can't move-assign if the types are not assignable,
// since we assign through the reference.
using P5 = std::pair<NotAssignable&, int>;
using P6 = std::pair<NotAssignable&&, int>;
static_assert(!std::is_move_assignable<P5>::value, "");
static_assert(!std::is_move_assignable<P6>::value, "");
}
return true;
}
int main(int, char**) {
test();
#if TEST_STD_VER >= 20
static_assert(test());
#endif
return 0;
}
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