78 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9// <tuple>10 11// constexpr const tuple& operator=(const tuple&) const;12//13// Constraints: (is_copy_assignable_v<const Types> && ...) is true.14 15// UNSUPPORTED: c++03, c++11, c++14, c++17, c++2016 17// test constraints18 19#include <cassert>20#include <tuple>21#include <type_traits>22 23#include "test_macros.h"24#include "copy_move_types.h"25 26static_assert(!std::is_assignable_v<const std::tuple<int>&, const std::tuple<int>&>);27static_assert(std::is_assignable_v<const std::tuple<int&>&, const std::tuple<int&>&>);28static_assert(std::is_assignable_v<const std::tuple<int&, int&>&, const std::tuple<int&, int&>&>);29static_assert(!std::is_assignable_v<const std::tuple<int&, int>&, const std::tuple<int&, int>&>);30static_assert(std::is_assignable_v<const std::tuple<ConstCopyAssign>&, const std::tuple<ConstCopyAssign>&>);31static_assert(!std::is_assignable_v<const std::tuple<CopyAssign>&, const std::tuple<CopyAssign>&>);32static_assert(!std::is_assignable_v<const std::tuple<ConstMoveAssign>&, const std::tuple<ConstMoveAssign>&>);33static_assert(!std::is_assignable_v<const std::tuple<MoveAssign>&, const std::tuple<MoveAssign>&>);34 35constexpr bool test() {36 // reference types37 {38 int i1 = 1;39 int i2 = 2;40 double d1 = 3.0;41 double d2 = 5.0;42 const std::tuple<int&, double&> t1{i1, d1};43 const std::tuple<int&, double&> t2{i2, d2};44 t2 = t1;45 assert(std::get<0>(t2) == 1);46 assert(std::get<1>(t2) == 3.0);47 }48 49 // user defined const copy assignment50 {51 const std::tuple<ConstCopyAssign> t1{1};52 const std::tuple<ConstCopyAssign> t2{2};53 t2 = t1;54 assert(std::get<0>(t2).val == 1);55 }56 57 // make sure the right assignment operator of the type in the tuple is used58 {59 std::tuple<TracedAssignment, const TracedAssignment> t1{};60 const std::tuple<TracedAssignment, const TracedAssignment> t2{};61 t2 = t1;62 assert(std::get<0>(t2).constCopyAssign == 1);63 assert(std::get<1>(t2).constCopyAssign == 1);64 }65 66 return true;67}68 69int main(int, char**) {70 test();71 72// gcc cannot have mutable member in constant expression73#if !defined(TEST_COMPILER_GCC)74 static_assert(test());75#endif76 return 0;77}78