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//===----------------------------------------------------------------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//
// <optional>
// template <class U> constexpr T optional<T>::value_or(U&& v) const&;
#include <experimental/optional>
#include <type_traits>
#include <cassert>
#if _LIBCPP_STD_VER > 11
using std::experimental::optional;
struct Y
{
int i_;
constexpr Y(int i) : i_(i) {}
};
struct X
{
int i_;
constexpr X(int i) : i_(i) {}
constexpr X(const Y& y) : i_(y.i_) {}
constexpr X(Y&& y) : i_(y.i_+1) {}
friend constexpr bool operator==(const X& x, const X& y)
{return x.i_ == y.i_;}
};
#endif // _LIBCPP_STD_VER > 11
int main()
{
#if _LIBCPP_STD_VER > 11
{
constexpr optional<X> opt(2);
constexpr Y y(3);
static_assert(opt.value_or(y) == 2, "");
}
{
constexpr optional<X> opt(2);
static_assert(opt.value_or(Y(3)) == 2, "");
}
{
constexpr optional<X> opt;
constexpr Y y(3);
static_assert(opt.value_or(y) == 3, "");
}
{
constexpr optional<X> opt;
static_assert(opt.value_or(Y(3)) == 4, "");
}
{
const optional<X> opt(2);
const Y y(3);
assert(opt.value_or(y) == 2);
}
{
const optional<X> opt(2);
assert(opt.value_or(Y(3)) == 2);
}
{
const optional<X> opt;
const Y y(3);
assert(opt.value_or(y) == 3);
}
{
const optional<X> opt;
assert(opt.value_or(Y(3)) == 4);
}
#endif // _LIBCPP_STD_VER > 11
}
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