80 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=(tuple&&) const;12//13// Constraints: (is_assignable_v<const Types&, 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>&, std::tuple<int>&&>);27static_assert(std::is_assignable_v<const std::tuple<int&>&, std::tuple<int&>&&>);28static_assert(std::is_assignable_v<const std::tuple<int&, int&>&, std::tuple<int&, int&>&&>);29static_assert(!std::is_assignable_v<const std::tuple<int&, int>&, std::tuple<int&, int>&&>);30 31// this is fallback to tuple's const copy assignment32static_assert(std::is_assignable_v<const std::tuple<ConstCopyAssign>&, std::tuple<ConstCopyAssign>&&>);33 34static_assert(!std::is_assignable_v<const std::tuple<CopyAssign>&, std::tuple<CopyAssign>&&>);35static_assert(std::is_assignable_v<const std::tuple<ConstMoveAssign>&, std::tuple<ConstMoveAssign>&&>);36static_assert(!std::is_assignable_v<const std::tuple<MoveAssign>&, std::tuple<MoveAssign>&&>);37 38constexpr bool test() {39 // reference types40 {41 int i1 = 1;42 int i2 = 2;43 double d1 = 3.0;44 double d2 = 5.0;45 std::tuple<int&, double&> t1{i1, d1};46 const std::tuple<int&, double&> t2{i2, d2};47 t2 = std::move(t1);48 assert(std::get<0>(t2) == 1);49 assert(std::get<1>(t2) == 3.0);50 }51 52 // user defined const move assignment53 {54 std::tuple<ConstMoveAssign> t1{1};55 const std::tuple<ConstMoveAssign> t2{2};56 t2 = std::move(t1);57 assert(std::get<0>(t2).val == 1);58 }59 60 // make sure the right assignment operator of the type in the tuple is used61 {62 std::tuple<TracedAssignment, const TracedAssignment> t1{};63 const std::tuple<TracedAssignment, const TracedAssignment> t2{};64 t2 = std::move(t1);65 assert(std::get<0>(t2).constMoveAssign == 1);66 assert(std::get<1>(t2).constCopyAssign == 1);67 }68 69 return true;70}71 72int main(int, char**) {73 test();74// gcc cannot have mutable member in constant expression75#if !defined(TEST_COMPILER_GCC)76 static_assert(test());77#endif78 return 0;79}80