//===----------------------------------------------------------------------===//
//
// 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;
// template <class U1, class U2>
// tuple& operator=(pair<U1, U2>&& u);
// UNSUPPORTED: c++03
#include <tuple>
#include <utility>
#include <memory>
#include <cassert>
#include "test_macros.h"
struct B
{
int id_;
explicit B(int i = 0) : id_(i) {}
virtual ~B() {}
};
struct D
: B
{
explicit D(int i) : B(i) {}
};
struct TrackMove
{
TrackMove() : value(0), moved_from(false) { }
explicit TrackMove(int v) : value(v), moved_from(false) { }
TrackMove(TrackMove const& other) : value(other.value), moved_from(false) { }
TrackMove(TrackMove&& other) : value(other.value), moved_from(false) {
other.moved_from = true;
}
TrackMove& operator=(TrackMove const& other) {
value = other.value;
moved_from = false;
return *this;
}
TrackMove& operator=(TrackMove&& other) {
value = other.value;
moved_from = false;
other.moved_from = true;
return *this;
}
int value;
bool moved_from;
};
struct NonAssignable
{
NonAssignable& operator=(NonAssignable const&) = delete;
NonAssignable& operator=(NonAssignable&&) = delete;
};
struct MoveAssignable
{
MoveAssignable& operator=(MoveAssignable const&) = delete;
MoveAssignable& operator=(MoveAssignable&&) = default;
};
struct CopyAssignable
{
CopyAssignable& operator=(CopyAssignable const&) = default;
CopyAssignable& operator=(CopyAssignable&&) = delete;
};
struct NothrowMoveAssignable
{
NothrowMoveAssignable& operator=(NothrowMoveAssignable&&) noexcept { return *this; }
};
struct PotentiallyThrowingMoveAssignable
{
PotentiallyThrowingMoveAssignable& operator=(PotentiallyThrowingMoveAssignable&&) { return *this; }
};
int main(int, char**)
{
{
typedef std::pair<long, std::unique_ptr<D>> T0;
typedef std::tuple<long long, std::unique_ptr<B>> T1;
T0 t0(2, std::unique_ptr<D>(new D(3)));
T1 t1;
t1 = std::move(t0);
assert(std::get<0>(t1) == 2);
assert(std::get<1>(t1)->id_ == 3);
}
{
using T = std::tuple<int, NonAssignable>;
using P = std::pair<int, NonAssignable>;
static_assert(!std::is_assignable<T&, P&&>::value, "");
}
{
using T = std::tuple<int, int, int>;
using P = std::pair<int, int>;
static_assert(!std::is_assignable<T&, P&&>::value, "");
}
{
typedef std::tuple<NothrowMoveAssignable, long> Tuple;
typedef std::pair<NothrowMoveAssignable, int> Pair;
static_assert(std::is_nothrow_assignable<Tuple&, Pair&&>::value, "");
static_assert(!std::is_assignable<Tuple&, Pair const&&>::value, "");
}
{
typedef std::tuple<PotentiallyThrowingMoveAssignable, long> Tuple;
typedef std::pair<PotentiallyThrowingMoveAssignable, int> Pair;
static_assert(std::is_assignable<Tuple&, Pair&&>::value, "");
static_assert(!std::is_nothrow_assignable<Tuple&, Pair&&>::value, "");
static_assert(!std::is_assignable<Tuple&, Pair const&&>::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 T = std::tuple<MoveAssignable&, int>;
using P = std::pair<MoveAssignable&, int>;
static_assert(!std::is_assignable<T&, P&&>::value, "");
}
// ... works if it's CopyAssignable
{
using T = std::tuple<CopyAssignable&, int>;
using P = std::pair<CopyAssignable&, int>;
static_assert(std::is_assignable<T&, P&&>::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 T1 = std::tuple<MoveAssignable&&, int>;
using P1 = std::pair<MoveAssignable&&, int>;
static_assert(std::is_assignable<T1&, P1&&>::value, "");
using T2 = std::tuple<CopyAssignable&&, int>;
using P2 = std::pair<CopyAssignable&&, int>;
static_assert(std::is_assignable<T2&, P2&&>::value, "");
}
// In all cases, we can't move-assign if the types are not assignable,
// since we assign through the reference.
{
using T1 = std::tuple<NonAssignable&, int>;
using P1 = std::pair<NonAssignable&, int>;
static_assert(!std::is_assignable<T1&, P1&&>::value, "");
using T2 = std::tuple<NonAssignable&&, int>;
using P2 = std::pair<NonAssignable&&, int>;
static_assert(!std::is_assignable<T2&, P2&&>::value, "");
}
}
{
// Make sure that we don't incorrectly move out of the source's reference.
using Dest = std::tuple<TrackMove, int>;
using Source = std::pair<TrackMove&, int>;
TrackMove track{3};
Source src(track, 4);
assert(!track.moved_from);
Dest dst;
dst = std::move(src); // here we should make a copy
assert(!track.moved_from);
assert(std::get<0>(dst).value == 3);
}
{
// But we do move out of the source's reference if it's a rvalue ref
using Dest = std::tuple<TrackMove, int>;
using Source = std::pair<TrackMove&&, int>;
TrackMove track{3};
Source src(std::move(track), 4);
assert(!track.moved_from); // we just took a reference
Dest dst;
dst = std::move(src);
assert(track.moved_from);
assert(std::get<0>(dst).value == 3);
}
{
// If the pair holds a value, then we move out of it too
using Dest = std::tuple<TrackMove, int>;
using Source = std::pair<TrackMove, int>;
Source src(TrackMove{3}, 4);
Dest dst;
dst = std::move(src);
assert(src.first.moved_from);
assert(std::get<0>(dst).value == 3);
}
return 0;
}
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