Differential D116621 Diff 439539 libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/non_const_pair.pass.cpp

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libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/non_const_pair.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... Types>
				// template <class U1, class U2>
				// constexpr explicit(see below) tuple<Types...>::tuple(pair<U1, U2>& u);

				// Constraints:
				// - sizeof...(Types) is 2 and
				// - is_constructible_v<T0, decltype(get<0>(FWD(u)))> is true and
				// - is_constructible_v<T1, decltype(get<1>(FWD(u)))> is true.

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

				#include <cassert>
				#include <tuple>
				#include <utility>

				#include "convert_types.h"

				// test constraints
				// sizeof...(Types) == 2
				static_assert(std::is_constructible_v<std::tuple<MutableCopy, int>, std::pair<MutableCopy, int>&>);

				static_assert(!std::is_constructible_v<std::tuple<MutableCopy>, std::pair<MutableCopy, int>&>);

				static_assert(!std::is_constructible_v<std::tuple<MutableCopy, int, int>, std::pair<MutableCopy, int>&>);

				// test constraints
				// is_constructible_v<T0, decltype(get<0>(FWD(u)))> is true and
				// is_constructible_v<T1, decltype(get<1>(FWD(u)))> is true.
				static_assert(std::is_constructible_v<std::tuple<int, int>, std::pair<int, int>&>);

				static_assert(!std::is_constructible_v<std::tuple<NoConstructorFromInt, int>, std::pair<int, int>&>);

				static_assert(!std::is_constructible_v<std::tuple<int, NoConstructorFromInt>, std::pair<int, int>&>);

				static_assert(!std::is_constructible_v< std::tuple<NoConstructorFromInt, NoConstructorFromInt>, std::pair<int, int>&>);

				// test: The expression inside explicit is equivalent to:
				// !is_convertible_v<decltype(get<0>(FWD(u))), T0> \|\|
				// !is_convertible_v<decltype(get<1>(FWD(u))), T1>
				static_assert(std::is_convertible_v<std::pair<MutableCopy, MutableCopy>&,
				std::tuple<ConvertibleFrom<MutableCopy>, ConvertibleFrom<MutableCopy>>>);

				static_assert(!std::is_convertible_v<std::pair<MutableCopy, MutableCopy>&,
				std::tuple<ExplicitConstructibleFrom<MutableCopy>, ConvertibleFrom<MutableCopy>>>);

				static_assert(!std::is_convertible_v<std::pair<MutableCopy, MutableCopy>&,
				std::tuple<ConvertibleFrom<MutableCopy>, ExplicitConstructibleFrom<MutableCopy>>>);

				constexpr bool test() {
				// test implicit conversions.
				{
				std::pair<MutableCopy, int> p{1, 2};
				std::tuple<ConvertibleFrom<MutableCopy>, ConvertibleFrom<int>> t = p;
				assert(std::get<0>(t).v.val == 1);
				assert(std::get<1>(t).v == 2);
				}

				// test explicit conversions.
				{
				std::pair<MutableCopy, int> p{1, 2};
				std::tuple<ExplicitConstructibleFrom<MutableCopy>, ExplicitConstructibleFrom<int>> t{p};
				assert(std::get<0>(t).v.val == 1);
				assert(std::get<1>(t).v == 2);
				}

				// non const overload should be called
				{
				std::pair<TracedCopyMove, TracedCopyMove> p;
				std::tuple<ConvertibleFrom<TracedCopyMove>, TracedCopyMove> t = p;
				assert(nonConstCopyCtrCalled(std::get<0>(t).v));
				assert(nonConstCopyCtrCalled(std::get<1>(t)));
				}

				return true;
				}

				int main() {
				test();
				static_assert(test());

				return 0;
				}