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 // <optional>
12
13 // template <class T, class U> constexpr bool operator==(const optional<T>& x, const U& v);
14 // template <class T, class U> constexpr bool operator==(const U& v, const optional<T>& x);
15
16 #include <optional>
17
18 using std::optional;
19
20 struct X {
21 int i_;
22
XX23 constexpr X(int i) : i_(i) {}
24 };
25
operator ==(const X & lhs,const X & rhs)26 constexpr bool operator==(const X& lhs, const X& rhs) {
27 return lhs.i_ == rhs.i_;
28 }
29
main()30 int main() {
31 {
32 typedef X T;
33 typedef optional<T> O;
34
35 constexpr T val(2);
36 constexpr O o1; // disengaged
37 constexpr O o2{1}; // engaged
38 constexpr O o3{val}; // engaged
39
40 static_assert(!(o1 == T(1)), "");
41 static_assert((o2 == T(1)), "");
42 static_assert(!(o3 == T(1)), "");
43 static_assert((o3 == T(2)), "");
44 static_assert((o3 == val), "");
45
46 static_assert(!(T(1) == o1), "");
47 static_assert((T(1) == o2), "");
48 static_assert(!(T(1) == o3), "");
49 static_assert((T(2) == o3), "");
50 static_assert((val == o3), "");
51 }
52 {
53 using O = optional<int>;
54 constexpr O o1(42);
55 static_assert(o1 == 42l, "");
56 static_assert(!(101l == o1), "");
57 }
58 {
59 using O = optional<const int>;
60 constexpr O o1(42);
61 static_assert(o1 == 42, "");
62 static_assert(!(101 == o1), "");
63 }
64 }
65