1 // I, Howard Hinnant, hereby place this code in the public domain. 2 3 // Test the "Augmented" template argument deduction when binding an lvalue to an rvalue reference. 4 5 // { dg-do compile { target c++11 } } 6 7 template <bool> struct sa; 8 template <> struct sa<true> {}; 9 10 template <class T, T v> 11 struct integral_constant 12 { 13 static const T value = v; 14 typedef T value_type; 15 typedef integral_constant<T, v> type; 16 }; 17 18 typedef integral_constant<bool, true> true_type; 19 typedef integral_constant<bool, false> false_type; 20 21 template <class T> struct is_lvalue_reference : public integral_constant<bool, false> {}; 22 template <class T> struct is_lvalue_reference<T&> : public integral_constant<bool, true> {}; 23 24 template <class T> struct is_rvalue_reference : public integral_constant<bool, false> {}; 25 template <class T> struct is_rvalue_reference<T&&> : public integral_constant<bool, true> {}; 26 27 template <bool is_lvalue_ref, bool is_rvalue_ref, class T> 28 void 29 test1(T&&) 30 { 31 sa<is_lvalue_reference<T&&>::value == is_lvalue_ref> t1; 32 sa<is_rvalue_reference<T&&>::value == is_rvalue_ref> t2; 33 } 34 35 template <bool is_lvalue_ref, bool is_rvalue_ref, class T> 36 void 37 test2(const T&&) // { dg-message "argument" } 38 { 39 sa<is_lvalue_reference<const T&&>::value == is_lvalue_ref> t1; 40 sa<is_rvalue_reference<const T&&>::value == is_rvalue_ref> t2; 41 } 42 43 template <bool is_lvalue_ref, bool is_rvalue_ref, class T> 44 void 45 test3(T*&&) 46 { 47 sa<is_lvalue_reference<T*&&>::value == is_lvalue_ref> t1; 48 sa<is_rvalue_reference<T*&&>::value == is_rvalue_ref> t2; 49 } 50 51 struct A {}; 52 53 A a; 54 55 A source() {return A();} 56 A* sourcep() {return 0;} 57 58 int main() 59 { 60 test1<true, false>(a); 61 test1<false, true>(source()); 62 test2<false, true>(a); // { dg-error "lvalue" } 63 test2<false, true>(source()); 64 test3<false, true>(&a); 65 test3<false, true>(sourcep()); 66 return 0; 67 } 68