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 // constexpr T&& optional<T>::operator*() &&; 14 15 #ifdef _LIBCPP_DEBUG 16 #define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : std::exit(0)) 17 #endif 18 19 #include <optional> 20 #include <type_traits> 21 #include <cassert> 22 23 #include "test_macros.h" 24 25 using std::optional; 26 27 struct X 28 { 29 constexpr int test() const& {return 3;} 30 int test() & {return 4;} 31 constexpr int test() const&& {return 5;} 32 int test() && {return 6;} 33 }; 34 35 struct Y 36 { 37 constexpr int test() && {return 7;} 38 }; 39 40 constexpr int 41 test() 42 { 43 optional<Y> opt{Y{}}; 44 return (*std::move(opt)).test(); 45 } 46 47 int main() 48 { 49 { 50 optional<X> opt; ((void)opt); 51 ASSERT_SAME_TYPE(decltype(*std::move(opt)), X&&); 52 // ASSERT_NOT_NOEXCEPT(*std::move(opt)); 53 // FIXME: This assertion fails with GCC because it can see that 54 // (A) operator*() is constexpr, and 55 // (B) there is no path through the function that throws. 56 // It's arguable if this is the correct behavior for the noexcept 57 // operator. 58 // Regardless this function should still be noexcept(false) because 59 // it has a narrow contract. 60 } 61 { 62 optional<X> opt(X{}); 63 assert((*std::move(opt)).test() == 6); 64 } 65 static_assert(test() == 7, ""); 66 #ifdef _LIBCPP_DEBUG 67 { 68 optional<X> opt; 69 assert((*std::move(opt)).test() == 3); 70 assert(false); 71 } 72 #endif // _LIBCPP_DEBUG 73 } 74
