test/std/utilities/optional/optional.relops/greater_than.pass.cpp

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++98, c++03, c++11, c++14
// <optional>

// template <class T, class U> constexpr bool operator> (const optional<T>& x, const optional<U>& y);

#include <optional>

using std::optional;

struct X {
  int i_;

  constexpr X(int i) : i_(i) {}
};

constexpr bool operator>(const X& lhs, const X& rhs) { return lhs.i_ > rhs.i_; }

int main() {
  {
    typedef optional<X> O;

    constexpr O o1;    // disengaged
    constexpr O o2;    // disengaged
    constexpr O o3{1}; // engaged
    constexpr O o4{2}; // engaged
    constexpr O o5{1}; // engaged

    static_assert(!(o1 > o1), "");
    static_assert(!(o1 > o2), "");
    static_assert(!(o1 > o3), "");
    static_assert(!(o1 > o4), "");
    static_assert(!(o1 > o5), "");

    static_assert(!(o2 > o1), "");
    static_assert(!(o2 > o2), "");
    static_assert(!(o2 > o3), "");
    static_assert(!(o2 > o4), "");
    static_assert(!(o2 > o5), "");

    static_assert((o3 > o1), "");
    static_assert((o3 > o2), "");
    static_assert(!(o3 > o3), "");
    static_assert(!(o3 > o4), "");
    static_assert(!(o3 > o5), "");

    static_assert((o4 > o1), "");
    static_assert((o4 > o2), "");
    static_assert((o4 > o3), "");
    static_assert(!(o4 > o4), "");
    static_assert((o4 > o5), "");

    static_assert((o5 > o1), "");
    static_assert((o5 > o2), "");
    static_assert(!(o5 > o3), "");
    static_assert(!(o5 > o4), "");
    static_assert(!(o5 > o5), "");
  }
  {
    using O1 = optional<int>;
    using O2 = optional<long>;
    constexpr O1 o1(42);
    static_assert(o1 > O2(1), "");
    static_assert(!(O2(42) > o1), "");
  }
  {
    using O1 = optional<int>;
    using O2 = optional<const int>;
    constexpr O1 o1(42);
    static_assert(o1 > O2(1), "");
    static_assert(!(O2(42) > o1), "");
  }
}