Differential D116621 Diff 439539 libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_convert_move.pass.cpp

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libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_convert_move.pass.cpp

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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... UTypes>
				// constexpr const tuple& operator=(tuple<UTypes...>&& u) const;
				//
				// Constraints:
				// - sizeof...(Types) equals sizeof...(UTypes) and
				// - (is_assignable_v<const Types&, UTypes> && ...) is true.

				// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20

				#include <cassert>
				#include <tuple>
				#include <type_traits>

				#include "test_macros.h"
				#include "types.h"

				// test constraints

				// sizeof...(Types) equals sizeof...(UTypes)
				static_assert(std::is_assignable_v<const std::tuple<int&>&, std::tuple<long&>&&>);
				static_assert(!std::is_assignable_v<const std::tuple<int&, int&>&, std::tuple<long&>&&>);
				static_assert(!std::is_assignable_v<const std::tuple<int&>&, std::tuple<long&, long&>&&>);

				// (is_assignable_v<const Types&, UTypes&&> && ...) is true
				static_assert(std::is_assignable_v<const std::tuple<AssignableFrom<ConstMoveAssign>>&, std::tuple<ConstMoveAssign>&&>);

				static_assert(std::is_assignable_v<const std::tuple<AssignableFrom<ConstMoveAssign>, ConstMoveAssign>&,
				std::tuple<ConstMoveAssign, ConstMoveAssign>&&>);

				static_assert(!std::is_assignable_v<const std::tuple<AssignableFrom<ConstMoveAssign>, AssignableFrom<MoveAssign>>&,
				std::tuple<ConstMoveAssign, MoveAssign>&&>);

				constexpr bool test() {
				// reference types
				{
				int i1 = 1;
				int i2 = 2;
				long j1 = 3;
				long j2 = 4;
				std::tuple<int&, int&> t1{i1, i2};
				const std::tuple<long&, long&> t2{j1, j2};
				t2 = std::move(t1);
				assert(std::get<0>(t2) == 1);
				assert(std::get<1>(t2) == 2);
				}

				// user defined const copy assignment
				{
				std::tuple<ConstMoveAssign> t1{1};
				const std::tuple<AssignableFrom<ConstMoveAssign>> t2{2};
				t2 = std::move(t1);
				assert(std::get<0>(t2).v.val == 1);
				}

				// make sure the right assignment operator of the type in the tuple is used
				{
				std::tuple<TracedAssignment> t1{};
				const std::tuple<AssignableFrom<TracedAssignment>> t2{};
				t2 = std::move(t1);
				assert(std::get<0>(t2).v.constMoveAssign == 1);
				}

				return true;
				}

				int main() {
				test();

				// gcc cannot have mutable member in constant expression
				#if !defined(TEST_COMPILER_GCC)
				static_assert(test());
				#endif
				return 0;
				}