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| 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-exception |
| 6 | +// |
| 7 | +//===----------------------------------------------------------------------===// |
| 8 | + |
| 9 | +// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20 |
| 10 | + |
| 11 | +// template <class O, class T> |
| 12 | +// struct out_value_result; |
| 13 | + |
| 14 | +#include <algorithm> |
| 15 | +#include <cassert> |
| 16 | +#include <type_traits> |
| 17 | + |
| 18 | +#include "MoveOnly.h" |
| 19 | + |
| 20 | +using std::ranges::out_value_result; |
| 21 | + |
| 22 | +// |
| 23 | +// Helper structs |
| 24 | +// |
| 25 | + |
| 26 | +// only explicit construction |
| 27 | +struct IterTypeExplicit { |
| 28 | + explicit IterTypeExplicit(int*); |
| 29 | +}; |
| 30 | + |
| 31 | +// implicit construction |
| 32 | +struct IterTypeImplicit { |
| 33 | + IterTypeImplicit(int*); |
| 34 | +}; |
| 35 | + |
| 36 | +struct IterTypeImplicitRef { |
| 37 | + IterTypeImplicitRef(int&); |
| 38 | +}; |
| 39 | + |
| 40 | +struct NotConvertible {}; |
| 41 | + |
| 42 | +template <class T> |
| 43 | +struct ConvertibleFrom { |
| 44 | + constexpr ConvertibleFrom(T c) : content{c} {} |
| 45 | + T content; |
| 46 | +}; |
| 47 | + |
| 48 | +// Standard layout classes can't have virtual functions |
| 49 | +struct NonStandardLayoutTypeBase { |
| 50 | + virtual ~NonStandardLayoutTypeBase(); |
| 51 | +}; |
| 52 | +struct NonStandardLayoutType : public NonStandardLayoutTypeBase {}; |
| 53 | + |
| 54 | +// |
| 55 | +constexpr bool test_constraints() { |
| 56 | + // requires convertible_to<const _OutIter1&, _OutIter2> && convertible_to<const _ValType1&, _ValType2> |
| 57 | + static_assert(std::is_constructible_v<out_value_result<int*, int>, out_value_result<int*, int>>); |
| 58 | + |
| 59 | + // test failure when implicit conversion isn't allowed |
| 60 | + static_assert(!std::is_constructible_v<out_value_result<IterTypeExplicit, int>, out_value_result<int*, int>>); |
| 61 | + |
| 62 | + // test success when implicit conversion is allowed, checking combinations of value, reference, and const |
| 63 | + static_assert(std::is_constructible_v<out_value_result<IterTypeImplicit, int>, out_value_result<int*, int>>); |
| 64 | + static_assert(std::is_constructible_v<out_value_result<IterTypeImplicit, int>, out_value_result<int*, int> const>); |
| 65 | + static_assert(std::is_constructible_v<out_value_result<IterTypeImplicit, int>, out_value_result<int*, int>&>); |
| 66 | + static_assert(std::is_constructible_v<out_value_result<IterTypeImplicit, int>, out_value_result<int*, int> const&>); |
| 67 | + |
| 68 | + static_assert(!std::is_constructible_v<out_value_result<IterTypeImplicitRef, int>, out_value_result<int, int>&>); |
| 69 | + |
| 70 | + // has to be convertible via const& |
| 71 | + static_assert(std::is_convertible_v<out_value_result<int, int>&, out_value_result<long, long>>); |
| 72 | + static_assert(std::is_convertible_v<const out_value_result<int, int>&, out_value_result<long, long>>); |
| 73 | + static_assert(std::is_convertible_v<out_value_result<int, int>&&, out_value_result<long, long>>); |
| 74 | + static_assert(std::is_convertible_v<const out_value_result<int, int>&&, out_value_result<long, long>>); |
| 75 | + |
| 76 | + // should be move constructible |
| 77 | + static_assert(std::is_move_constructible_v<out_value_result<MoveOnly, int>>); |
| 78 | + static_assert(std::is_move_constructible_v<out_value_result<int, MoveOnly>>); |
| 79 | + |
| 80 | + // conversions should not work if there is no conversion |
| 81 | + static_assert(!std::is_convertible_v<out_value_result<NotConvertible, int>, out_value_result<int, NotConvertible>>); |
| 82 | + static_assert(!std::is_convertible_v<out_value_result<int, NotConvertible>, out_value_result<NotConvertible, int>>); |
| 83 | + |
| 84 | + // check standard layout |
| 85 | + static_assert(std::is_standard_layout_v<out_value_result<int, int>>); |
| 86 | + static_assert(!std::is_standard_layout_v<out_value_result<NonStandardLayoutType, int>>); |
| 87 | + |
| 88 | + return true; |
| 89 | +} |
| 90 | + |
| 91 | +// Test results |
| 92 | +constexpr bool test() { |
| 93 | + { |
| 94 | + // Check that conversion operator works |
| 95 | + out_value_result<double, int> res{10, 1}; |
| 96 | + assert(res.out == 10); |
| 97 | + assert(res.value == 1); |
| 98 | + out_value_result<ConvertibleFrom<double>, ConvertibleFrom<int>> res2 = res; |
| 99 | + assert(res2.out.content == 10); |
| 100 | + assert(res2.value.content == 1); |
| 101 | + } |
| 102 | + { |
| 103 | + // Check that out_value_result isn't overconstrained w.r.t. move/copy constructors |
| 104 | + out_value_result<MoveOnly, int> res{MoveOnly{}, 10}; |
| 105 | + assert(res.out.get() == 1); |
| 106 | + assert(res.value == 10); |
| 107 | + auto res2 = std::move(res); |
| 108 | + assert(res.out.get() == 0); |
| 109 | + assert(res.value == 10); |
| 110 | + assert(res2.out.get() == 1); |
| 111 | + assert(res2.value == 10); |
| 112 | + } |
| 113 | + { |
| 114 | + // Check structured binding |
| 115 | + auto [out, val] = out_value_result<int, int>{1, 2}; |
| 116 | + assert(out == 1); |
| 117 | + assert(val == 2); |
| 118 | + } |
| 119 | + { |
| 120 | + // Check default construction |
| 121 | + out_value_result<int, double> res; |
| 122 | + static_assert(std::is_same_v<int, decltype(res.out)>); |
| 123 | + static_assert(std::is_same_v<double, decltype(res.value)>); |
| 124 | + } |
| 125 | + { |
| 126 | + // Check aggregate initiazliation |
| 127 | + out_value_result<int, int> res = {1, 2}; |
| 128 | + assert(res.out == 1); |
| 129 | + assert(res.value == 2); |
| 130 | + } |
| 131 | + |
| 132 | + return true; |
| 133 | +} |
| 134 | + |
| 135 | +int main(int, char**) { |
| 136 | + test_constraints(); |
| 137 | + static_assert(test_constraints()); |
| 138 | + test(); |
| 139 | + static_assert(test()); |
| 140 | + return 0; |
| 141 | +} |
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