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

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libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_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>

				// constexpr const tuple& operator=(tuple&&) const;
				//
				// Constraints: (is_assignable_v<const Types&, Types> && ...) is true.

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

				// test constraints

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

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

				static_assert(!std::is_assignable_v<const std::tuple<int>&, std::tuple<int>&&>);
				static_assert(std::is_assignable_v<const std::tuple<int&>&, std::tuple<int&>&&>);
				static_assert(std::is_assignable_v<const std::tuple<int&, int&>&, std::tuple<int&, int&>&&>);
				static_assert(!std::is_assignable_v<const std::tuple<int&, int>&, std::tuple<int&, int>&&>);

				// this is fallback to tuple's const copy assignment
				static_assert(std::is_assignable_v<const std::tuple<ConstCopyAssign>&, std::tuple<ConstCopyAssign>&&>);

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

				constexpr bool test() {
				// reference types
				{
				int i1 = 1;
				int i2 = 2;
				double d1 = 3.0;
				double d2 = 5.0;
				std::tuple<int&, double&> t1{i1, d1};
				const std::tuple<int&, double&> t2{i2, d2};
				t2 = std::move(t1);
				assert(std::get<0>(t2) == 1);
				assert(std::get<1>(t2) == 3.0);
				}

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

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