// DR 339 // // Test of the use of the function call operator with SFINAE typedef char yes_type; struct no_type { char data[2]; }; template<typename T> T create_a(); template<typename T> struct type { }; template<bool, typename T = void> struct enable_if { typedef T type; }; template<typename T> struct enable_if<false, T> { }; template<typename F, typename T1, typename T2> typename enable_if<sizeof(create_a<F>()(create_a<T1>(), create_a<T2>()), 1), yes_type>::type check_is_callable2(type<F>, type<T1>, type<T2>); no_type check_is_callable2(...); template<typename F, typename T1, typename T2 = T1> struct is_callable2 { static const bool value = (sizeof(check_is_callable2(type<F>(), type<T1>(), type<T2>())) == sizeof(yes_type)); // { dg-error "within this context" } }; #define JOIN( X, Y ) DO_JOIN( X, Y ) #define DO_JOIN( X, Y ) DO_JOIN2(X,Y) #define DO_JOIN2( X, Y ) X##Y #ifdef __GXX_EXPERIMENTAL_CXX0X__ # define STATIC_ASSERT(Expr) static_assert(Expr, #Expr) #else # define STATIC_ASSERT(Expr) int JOIN(a,__LINE__)[Expr? 1 : -1] #endif struct A; struct B; struct A { A(B); }; struct B { B(A); }; struct F { void operator()(A, A); private: void operator()(B, B); // { dg-error "is private" } }; STATIC_ASSERT((is_callable2<F, B, B>::value));