1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // UNSUPPORTED: c++98, c++03, c++11, c++14
11 
12 // <optional>
13 
14 // template <class U>
15 //   constexpr EXPLICIT optional(U&& u);
16 
17 #include <optional>
18 #include <type_traits>
19 #include <cassert>
20 
21 #include "test_macros.h"
22 #include "archetypes.hpp"
23 #include "test_convertible.hpp"
24 
25 
26 using std::optional;
27 
28 struct ImplicitThrow
29 {
30     constexpr ImplicitThrow(int x) { if (x != -1) TEST_THROW(6);}
31 };
32 
33 struct ExplicitThrow
34 {
35     constexpr explicit ExplicitThrow(int x) { if (x != -1) TEST_THROW(6);}
36 };
37 
38 
39 template <class To, class From>
40 constexpr bool implicit_conversion(optional<To>&& opt, const From& v)
41 {
42     using O = optional<To>;
43     static_assert(test_convertible<O, From>(), "");
44     static_assert(!test_convertible<O, void*>(), "");
45     static_assert(!test_convertible<O, From, int>(), "");
46     return opt && *opt == static_cast<To>(v);
47 }
48 
49 template <class To, class Input, class Expect>
50 constexpr bool explicit_conversion(Input&& in, const Expect& v)
51 {
52     using O = optional<To>;
53     static_assert(std::is_constructible<O, Input>::value, "");
54     static_assert(!std::is_convertible<Input, O>::value, "");
55     static_assert(!std::is_constructible<O, void*>::value, "");
56     static_assert(!std::is_constructible<O, Input, int>::value, "");
57     optional<To> opt(std::forward<Input>(in));
58     return opt && *opt == static_cast<To>(v);
59 }
60 
61 void test_implicit()
62 {
63     {
64         using T = long long;
65         static_assert(implicit_conversion<long long>(42, 42), "");
66     }
67     {
68         using T = long double;
69         static_assert(implicit_conversion<long double>(3.14, 3.14), "");
70     }
71     {
72         int x = 42;
73         optional<void* const> o(&x);
74         assert(*o == &x);
75     }
76     {
77         using T = TrivialTestTypes::TestType;
78         static_assert(implicit_conversion<T>(42, 42), "");
79     }
80     {
81         using T = TestTypes::TestType;
82         assert(implicit_conversion<T>(3, T(3)));
83     }
84 #ifndef TEST_HAS_NO_EXCEPTIONS
85     {
86         try {
87             using T = ImplicitThrow;
88             optional<T> t = 42;
89             assert(false);
90         } catch (int) {
91         }
92     }
93 #endif
94 }
95 
96 void test_explicit() {
97     {
98         using T = ExplicitTrivialTestTypes::TestType;
99         using O = optional<T>;
100         static_assert(explicit_conversion<T>(42, 42), "");
101     }
102     {
103         using T = ExplicitConstexprTestTypes::TestType;
104         using O = optional<T>;
105         static_assert(explicit_conversion<T>(42, 42), "");
106         static_assert(!std::is_convertible<int, T>::value, "");
107     }
108     {
109         using T = ExplicitTestTypes::TestType;
110         using O = optional<T>;
111         T::reset();
112         {
113             assert(explicit_conversion<T>(42, 42));
114             assert(T::alive == 0);
115         }
116         T::reset();
117         {
118             optional<T> t(42);
119             assert(T::alive == 1);
120             assert(T::value_constructed == 1);
121             assert(T::move_constructed == 0);
122             assert(T::copy_constructed == 0);
123             assert(t.value().value == 42);
124         }
125         assert(T::alive == 0);
126     }
127 #ifndef TEST_HAS_NO_EXCEPTIONS
128     {
129         try {
130             using T = ExplicitThrow;
131             optional<T> t(42);
132             assert(false);
133         } catch (int) {
134         }
135     }
136 #endif
137 }
138 
139 int main() {
140     test_implicit();
141     test_explicit();
142 }
143