#include <iostream>
#include <string>
 
class X {};
 
template<typename T>
inline auto foo(T && rhs) -> decltype(foohelper(std::forward<T>(rhs), 0)) {
    return foohelper(std::forward<T>(rhs), 0);
}
 
template<typename T>
inline auto foohelper(T && rhs, int) -> decltype(fooimpl(std::forward<T>(rhs))) {
    return fooimpl(std::forward<T>(rhs));
}
 
template<typename T>
inline std::string foohelper(T && rhs, long) {
    return "bad";
}
 
inline std::string fooimpl(const X & rhs) {
    return "good";
}
 
int main() {
    std::cout << foo(X()) << std::endl;
    X x;
    std::cout << foo(x) << std::endl;
    return 0;
}
 

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