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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
//
//===----------------------------------------------------------------------===//
// <tuple>
// template <class... Types> class tuple;
// tuple& operator=(tuple&& u);
// UNSUPPORTED: c++03
#include <memory>
#include <tuple>
#include <utility>
#include <cassert>
#include "test_macros.h"
#include "MoveOnly.h"
struct NonAssignable {
NonAssignable& operator=(NonAssignable const&) = delete;
NonAssignable& operator=(NonAssignable&&) = delete;
};
struct CopyAssignable {
CopyAssignable& operator=(CopyAssignable const&) = default;
CopyAssignable& operator=(CopyAssignable&&) = delete;
};
static_assert(std::is_copy_assignable<CopyAssignable>::value, "");
struct MoveAssignable {
MoveAssignable& operator=(MoveAssignable const&) = delete;
MoveAssignable& operator=(MoveAssignable&&) = default;
};
struct NothrowMoveAssignable {
NothrowMoveAssignable& operator=(NothrowMoveAssignable&&) noexcept { return *this; }
};
struct PotentiallyThrowingMoveAssignable {
PotentiallyThrowingMoveAssignable& operator=(PotentiallyThrowingMoveAssignable&&) { return *this; }
};
struct CountAssign {
static int copied;
static int moved;
static void reset() { copied = moved = 0; }
CountAssign() = default;
CountAssign& operator=(CountAssign const&) { ++copied; return *this; }
CountAssign& operator=(CountAssign&&) { ++moved; return *this; }
};
int CountAssign::copied = 0;
int CountAssign::moved = 0;
TEST_CONSTEXPR_CXX20
bool test()
{
{
typedef std::tuple<> T;
T t0;
T t;
t = std::move(t0);
}
{
typedef std::tuple<MoveOnly> T;
T t0(MoveOnly(0));
T t;
t = std::move(t0);
assert(std::get<0>(t) == 0);
}
{
typedef std::tuple<MoveOnly, MoveOnly> T;
T t0(MoveOnly(0), MoveOnly(1));
T t;
t = std::move(t0);
assert(std::get<0>(t) == 0);
assert(std::get<1>(t) == 1);
}
{
typedef std::tuple<MoveOnly, MoveOnly, MoveOnly> T;
T t0(MoveOnly(0), MoveOnly(1), MoveOnly(2));
T t;
t = std::move(t0);
assert(std::get<0>(t) == 0);
assert(std::get<1>(t) == 1);
assert(std::get<2>(t) == 2);
}
{
// test reference assignment.
using T = std::tuple<int&, int&&>;
int x = 42;
int y = 100;
int x2 = -1;
int y2 = 500;
T t(x, std::move(y));
T t2(x2, std::move(y2));
t = std::move(t2);
assert(std::get<0>(t) == x2);
assert(&std::get<0>(t) == &x);
assert(std::get<1>(t) == y2);
assert(&std::get<1>(t) == &y);
}
return true;
}
int main(int, char**)
{
test();
#if TEST_STD_VER >= 20
static_assert(test());
#endif
{
// test that the implicitly generated move assignment operator
// is properly deleted
using T = std::tuple<std::unique_ptr<int>>;
static_assert(std::is_move_assignable<T>::value, "");
static_assert(!std::is_copy_assignable<T>::value, "");
}
{
using T = std::tuple<int, NonAssignable>;
static_assert(!std::is_move_assignable<T>::value, "");
}
{
using T = std::tuple<int, MoveAssignable>;
static_assert(std::is_move_assignable<T>::value, "");
}
{
// The move should decay to a copy.
CountAssign::reset();
using T = std::tuple<CountAssign, CopyAssignable>;
static_assert(std::is_move_assignable<T>::value, "");
T t1;
T t2;
t1 = std::move(t2);
assert(CountAssign::copied == 1);
assert(CountAssign::moved == 0);
}
{
using T = std::tuple<int, NonAssignable>;
static_assert(!std::is_move_assignable<T>::value, "");
}
{
using T = std::tuple<int, MoveAssignable>;
static_assert(std::is_move_assignable<T>::value, "");
}
{
using T = std::tuple<NothrowMoveAssignable, int>;
static_assert(std::is_nothrow_move_assignable<T>::value, "");
}
{
using T = std::tuple<PotentiallyThrowingMoveAssignable, int>;
static_assert(!std::is_nothrow_move_assignable<T>::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 T1 = std::tuple<MoveAssignable&, int>;
static_assert(!std::is_move_assignable<T1>::value, "");
// ... works if it's CopyAssignable
using T2 = std::tuple<CopyAssignable&, int>;
static_assert(std::is_move_assignable<T2>::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 T3 = std::tuple<MoveAssignable&&, int>;
using T4 = std::tuple<CopyAssignable&&, int>;
static_assert(std::is_move_assignable<T3>::value, "");
static_assert(std::is_move_assignable<T4>::value, "");
// In all cases, we can't move-assign if the types are not assignable,
// since we assign through the reference.
using T5 = std::tuple<NonAssignable&, int>;
using T6 = std::tuple<NonAssignable&&, int>;
static_assert(!std::is_move_assignable<T5>::value, "");
static_assert(!std::is_move_assignable<T6>::value, "");
}
return 0;
}
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