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 // type_traits 11 12 // add_lvalue_reference 13 // If T names a referenceable type then the member typedef type 14 // shall name T&; otherwise, type shall name T. 15 16 #include <type_traits> 17 #include "test_macros.h" 18 19 template <class T, class U> 20 void test_add_lvalue_reference() 21 { 22 static_assert((std::is_same<typename std::add_lvalue_reference<T>::type, U>::value), ""); 23 #if TEST_STD_VER > 11 24 static_assert((std::is_same<std::add_lvalue_reference_t<T>, U>::value), ""); 25 #endif 26 } 27 28 template <class F> 29 void test_function0() 30 { 31 static_assert((std::is_same<typename std::add_lvalue_reference<F>::type, F&>::value), ""); 32 #if TEST_STD_VER > 11 33 static_assert((std::is_same<std::add_lvalue_reference_t<F>, F&>::value), ""); 34 #endif 35 } 36 37 template <class F> 38 void test_function1() 39 { 40 static_assert((std::is_same<typename std::add_lvalue_reference<F>::type, F>::value), ""); 41 #if TEST_STD_VER > 11 42 static_assert((std::is_same<std::add_lvalue_reference_t<F>, F>::value), ""); 43 #endif 44 } 45 46 struct Foo {}; 47 48 int main() 49 { 50 test_add_lvalue_reference<void, void>(); 51 test_add_lvalue_reference<int, int&>(); 52 test_add_lvalue_reference<int[3], int(&)[3]>(); 53 test_add_lvalue_reference<int&, int&>(); 54 test_add_lvalue_reference<const int&, const int&>(); 55 test_add_lvalue_reference<int*, int*&>(); 56 test_add_lvalue_reference<const int*, const int*&>(); 57 test_add_lvalue_reference<Foo, Foo&>(); 58 59 // LWG 2101 specifically talks about add_lvalue_reference and functions. 60 // The term of art is "a referenceable type", which a cv- or ref-qualified function is not. 61 test_function0<void()>(); 62 #if TEST_STD_VER >= 11 63 test_function1<void() const>(); 64 test_function1<void() &>(); 65 test_function1<void() &&>(); 66 test_function1<void() const &>(); 67 test_function1<void() const &&>(); 68 #endif 69 70 // But a cv- or ref-qualified member function *is* "a referenceable type" 71 test_function0<void (Foo::*)()>(); 72 #if TEST_STD_VER >= 11 73 test_function0<void (Foo::*)() const>(); 74 test_function0<void (Foo::*)() &>(); 75 test_function0<void (Foo::*)() &&>(); 76 test_function0<void (Foo::*)() const &>(); 77 test_function0<void (Foo::*)() const &&>(); 78 #endif 79 } 80
