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 // <optional> 11 12 // constexpr optional(nullopt_t) noexcept; 13 14 #include <experimental/optional> 15 #include <type_traits> 16 #include <cassert> 17 18 #if _LIBCPP_STD_VER > 11 19 20 using std::experimental::optional; 21 using std::experimental::nullopt_t; 22 using std::experimental::nullopt; 23 24 template <class Opt> 25 void 26 test_constexpr() 27 { 28 static_assert(noexcept(Opt(nullopt)), ""); 29 constexpr Opt opt(nullopt); 30 static_assert(static_cast<bool>(opt) == false, ""); 31 32 struct test_constexpr_ctor 33 : public Opt 34 { 35 constexpr test_constexpr_ctor() {} 36 }; 37 } 38 39 template <class Opt> 40 void 41 test() 42 { 43 static_assert(noexcept(Opt(nullopt)), ""); 44 Opt opt(nullopt); 45 assert(static_cast<bool>(opt) == false); 46 47 struct test_constexpr_ctor 48 : public Opt 49 { 50 constexpr test_constexpr_ctor() {} 51 }; 52 } 53 54 struct X 55 { 56 X(); 57 }; 58 59 #endif // _LIBCPP_STD_VER > 11 60 61 int main() 62 { 63 #if _LIBCPP_STD_VER > 11 64 test_constexpr<optional<int>>(); 65 test_constexpr<optional<int*>>(); 66 test<optional<X>>(); 67 #endif // _LIBCPP_STD_VER > 11 68 } 69
