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 optional<U>& y);
14
15 #include <optional>
16
17 using std::optional;
18
19 struct X {
20 int i_;
21
XX22 constexpr X(int i) : i_(i) {}
23 };
24
operator <(const X & lhs,const X & rhs)25 constexpr bool operator<(const X& lhs, const X& rhs) { return lhs.i_ < rhs.i_; }
26
main()27 int main() {
28 {
29 typedef optional<X> O;
30
31 constexpr O o1; // disengaged
32 constexpr O o2; // disengaged
33 constexpr O o3{1}; // engaged
34 constexpr O o4{2}; // engaged
35 constexpr O o5{1}; // engaged
36
37 static_assert(!(o1 < o1), "");
38 static_assert(!(o1 < o2), "");
39 static_assert((o1 < o3), "");
40 static_assert((o1 < o4), "");
41 static_assert((o1 < o5), "");
42
43 static_assert(!(o2 < o1), "");
44 static_assert(!(o2 < o2), "");
45 static_assert((o2 < o3), "");
46 static_assert((o2 < o4), "");
47 static_assert((o2 < o5), "");
48
49 static_assert(!(o3 < o1), "");
50 static_assert(!(o3 < o2), "");
51 static_assert(!(o3 < o3), "");
52 static_assert((o3 < o4), "");
53 static_assert(!(o3 < o5), "");
54
55 static_assert(!(o4 < o1), "");
56 static_assert(!(o4 < o2), "");
57 static_assert(!(o4 < o3), "");
58 static_assert(!(o4 < o4), "");
59 static_assert(!(o4 < o5), "");
60
61 static_assert(!(o5 < o1), "");
62 static_assert(!(o5 < o2), "");
63 static_assert(!(o5 < o3), "");
64 static_assert((o5 < o4), "");
65 static_assert(!(o5 < o5), "");
66 }
67 {
68 using O1 = optional<int>;
69 using O2 = optional<long>;
70 constexpr O1 o1(42);
71 static_assert(o1 < O2(101), "");
72 static_assert(!(O2(101) < o1), "");
73 }
74 {
75 using O1 = optional<int>;
76 using O2 = optional<const int>;
77 constexpr O1 o1(42);
78 static_assert(o1 < O2(101), "");
79 static_assert(!(O2(101) < o1), "");
80 }
81 }
82