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 // <expected>
12
13 // template<class F> constexpr auto or_else(F&& f) &;
14 // template<class F> constexpr auto or_else(F&& f) const &;
15 // template<class F> constexpr auto or_else(F&& f) &&;
16 // template<class F> constexpr auto or_else(F&& f) const &&;
17
18 #include <expected>
19 #include <concepts>
20 #include <cassert>
21 #include <type_traits>
22 #include <utility>
23
test_val_types()24 constexpr void test_val_types() {
25 // Test & overload
26 {
27 auto l = [](auto) -> std::expected<void, long> { return {}; };
28 std::expected<void, int> v(std::unexpected<int>(1));
29 std::same_as<std::expected<void, long>> decltype(auto) val = v.or_else(l);
30 assert(val.has_value());
31 }
32
33 // Test const& overload
34 {
35 auto l = [](auto) -> std::expected<void, long> { return {}; };
36 const std::expected<void, int> v(std::unexpected<int>(1));
37 std::same_as<std::expected<void, long>> decltype(auto) val = v.or_else(l);
38 assert(val.has_value());
39 }
40
41 // Test && overload
42 {
43 auto l = [](auto) -> std::expected<void, long> { return {}; };
44 std::expected<void, int> v(std::unexpected<int>(1));
45 std::same_as<std::expected<void, long>> decltype(auto) val = std::move(v).or_else(l);
46 assert(val.has_value());
47 }
48
49 // Test const&& overload
50 {
51 auto l = [](auto) -> std::expected<void, long> { return {}; };
52 const std::expected<void, int> v(std::unexpected<int>(1));
53 std::same_as<std::expected<void, long>> decltype(auto) val = std::move(v).or_else(l);
54 assert(val.has_value());
55 }
56 }
57
test_fail()58 constexpr void test_fail() {
59 auto never_called = [](auto) -> std::expected<void, long> {
60 assert(false);
61 return std::expected<void, long>(std::unexpected<long>(5));
62 };
63
64 // Test & overload
65 {
66 std::expected<void, int> v;
67 std::same_as<std::expected<void, long>> decltype(auto) val = v.or_else(never_called);
68 assert(val.has_value());
69 }
70
71 // Test const& overload
72 {
73 const std::expected<void, int> v;
74 std::same_as<std::expected<void, long>> decltype(auto) val = v.or_else(never_called);
75 assert(val.has_value());
76 }
77
78 // Test && overload
79 {
80 std::expected<void, int> v;
81 std::same_as<std::expected<void, long>> decltype(auto) val = std::move(v).or_else(never_called);
82 assert(val.has_value());
83 }
84
85 // Test const&& overload
86 {
87 const std::expected<void, int> v;
88 std::same_as<std::expected<void, long>> decltype(auto) val = std::move(v).or_else(never_called);
89 assert(val.has_value());
90 }
91 }
92
test()93 constexpr bool test() {
94 test_fail();
95 test_val_types();
96 return true;
97 }
98
main(int,char **)99 int main(int, char**) {
100 test();
101 static_assert(test());
102
103 return 0;
104 }
105