90 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// template<class U1, class U2>12// constexpr const tuple& operator=(const pair<U1, U2>& u) const;13//14// - sizeof...(Types) is 2,15// - is_assignable_v<const T1&, const U1&> is true, and16// - is_assignable_v<const T2&, const U2&> is true17 18// UNSUPPORTED: c++03, c++11, c++14, c++17, c++2019 20#include <cassert>21#include <tuple>22#include <type_traits>23#include <utility>24 25#include "test_macros.h"26#include "copy_move_types.h"27 28// test constraints29 30// sizeof...(Types) != 2,31static_assert(std::is_assignable_v<const std::tuple<int&, int&>&, const std::pair<int&, int&>&>);32static_assert(!std::is_assignable_v<const std::tuple<int&>&, const std::pair<int&, int&>&>);33static_assert(!std::is_assignable_v<const std::tuple<int&, int&, int&>&, const std::pair<int&, int&>&>);34 35static_assert(std::is_assignable_v<const std::tuple<AssignableFrom<ConstCopyAssign>, ConstCopyAssign>&,36 const std::pair<ConstCopyAssign, ConstCopyAssign>&>);37 38// is_assignable_v<const T1&, const U1&> is false39static_assert(!std::is_assignable_v<const std::tuple<AssignableFrom<CopyAssign>, ConstCopyAssign>&,40 const std::pair<CopyAssign, ConstCopyAssign>&>);41 42// is_assignable_v<const T2&, const U2&> is false43static_assert(!std::is_assignable_v<const std::tuple<AssignableFrom<ConstCopyAssign>, AssignableFrom<CopyAssign>>&,44 const std::tuple<ConstCopyAssign, CopyAssign>&>);45 46constexpr bool test() {47 // reference types48 {49 int i1 = 1;50 int i2 = 2;51 long j1 = 3;52 long j2 = 4;53 const std::pair<int&, int&> t1{i1, i2};54 const std::tuple<long&, long&> t2{j1, j2};55 t2 = t1;56 assert(std::get<0>(t2) == 1);57 assert(std::get<1>(t2) == 2);58 }59 60 // user defined const copy assignment61 {62 const std::pair<ConstCopyAssign, ConstCopyAssign> t1{1, 2};63 const std::tuple<AssignableFrom<ConstCopyAssign>, ConstCopyAssign> t2{3, 4};64 t2 = t1;65 assert(std::get<0>(t2).v.val == 1);66 assert(std::get<1>(t2).val == 2);67 }68 69 // make sure the right assignment operator of the type in the tuple is used70 {71 std::pair<TracedAssignment, TracedAssignment> t1{};72 const std::tuple<AssignableFrom<TracedAssignment>, AssignableFrom<TracedAssignment>> t2{};73 t2 = t1;74 assert(std::get<0>(t2).v.constCopyAssign == 1);75 assert(std::get<1>(t2).v.constCopyAssign == 1);76 }77 78 return true;79}80 81int main(int, char**) {82 test();83 84// gcc cannot have mutable member in constant expression85#if !defined(TEST_COMPILER_GCC)86 static_assert(test());87#endif88 return 0;89}90