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 U> constexpr T optional<T>::value_or(U&& v) const&; 14 15 #include <optional> 16 #include <type_traits> 17 #include <cassert> 18 19 using std::optional; 20 21 struct Y 22 { 23 int i_; 24 25 constexpr Y(int i) : i_(i) {} 26 }; 27 28 struct X 29 { 30 int i_; 31 32 constexpr X(int i) : i_(i) {} 33 constexpr X(const Y& y) : i_(y.i_) {} 34 constexpr X(Y&& y) : i_(y.i_+1) {} 35 friend constexpr bool operator==(const X& x, const X& y) 36 {return x.i_ == y.i_;} 37 }; 38 39 int main() 40 { 41 { 42 constexpr optional<X> opt(2); 43 constexpr Y y(3); 44 static_assert(opt.value_or(y) == 2, ""); 45 } 46 { 47 constexpr optional<X> opt(2); 48 static_assert(opt.value_or(Y(3)) == 2, ""); 49 } 50 { 51 constexpr optional<X> opt; 52 constexpr Y y(3); 53 static_assert(opt.value_or(y) == 3, ""); 54 } 55 { 56 constexpr optional<X> opt; 57 static_assert(opt.value_or(Y(3)) == 4, ""); 58 } 59 { 60 const optional<X> opt(2); 61 const Y y(3); 62 assert(opt.value_or(y) == 2); 63 } 64 { 65 const optional<X> opt(2); 66 assert(opt.value_or(Y(3)) == 2); 67 } 68 { 69 const optional<X> opt; 70 const Y y(3); 71 assert(opt.value_or(y) == 3); 72 } 73 { 74 const optional<X> opt; 75 assert(opt.value_or(Y(3)) == 4); 76 } 77 } 78
