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         static_assert(implicit_conversion<long long>(42, 42), "");
65     }
66     {
67         static_assert(implicit_conversion<long double>(3.14, 3.14), "");
68     }
69     {
70         int x = 42;
71         optional<void* const> o(&x);
72         assert(*o == &x);
73     }
74     {
75         using T = TrivialTestTypes::TestType;
76         static_assert(implicit_conversion<T>(42, 42), "");
77     }
78     {
79         using T = TestTypes::TestType;
80         assert(implicit_conversion<T>(3, T(3)));
81     }
82 #ifndef TEST_HAS_NO_EXCEPTIONS
83     {
84         try {
85             using T = ImplicitThrow;
86             optional<T> t = 42;
87             assert(false);
88             ((void)t);
89         } catch (int) {
90         }
91     }
92 #endif
93 }
94 
95 void test_explicit() {
96     {
97         using T = ExplicitTrivialTestTypes::TestType;
98         static_assert(explicit_conversion<T>(42, 42), "");
99     }
100     {
101         using T = ExplicitConstexprTestTypes::TestType;
102         static_assert(explicit_conversion<T>(42, 42), "");
103         static_assert(!std::is_convertible<int, T>::value, "");
104     }
105     {
106         using T = ExplicitTestTypes::TestType;
107         T::reset();
108         {
109             assert(explicit_conversion<T>(42, 42));
110             assert(T::alive == 0);
111         }
112         T::reset();
113         {
114             optional<T> t(42);
115             assert(T::alive == 1);
116             assert(T::value_constructed == 1);
117             assert(T::move_constructed == 0);
118             assert(T::copy_constructed == 0);
119             assert(t.value().value == 42);
120         }
121         assert(T::alive == 0);
122     }
123 #ifndef TEST_HAS_NO_EXCEPTIONS
124     {
125         try {
126             using T = ExplicitThrow;
127             optional<T> t(42);
128             assert(false);
129         } catch (int) {
130         }
131     }
132 #endif
133 }
134 
135 int main() {
136     test_implicit();
137     test_explicit();
138 }
139