#include <iostream>
#include <string>
 
class X {};
 
template<typename T>
inline std::string foo(T && rhs) {
    return "bad";
}
 
inline std::string foo(const X & rhs) {
    return "good const &";
}
 
inline std::string foo(X & rhs) {
    return "good &";
}
 
inline std::string foo(X && rhs) {
    return "good &&";
}
 
int main() {
    std::cout << foo(X()) << std::endl;
    X x;
    std::cout << foo(x) << std::endl;
    std::cout << foo(static_cast<X const &>(x)) << std::endl;
    return 0;
}

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