Here is a solution for C++ based on operator overloading. It relies on implicit conversion from an enum to an int.

#include <iostream>

enum X {};
bool operator==(X x, int y)
{
    return true;
}

int main()
{
    X x;
    std::cout << ((x == x+2) ? "true" : "false") << std::endl;
    return 0;
}

Here is a solution for C++ based on operator overloading. It relies on implicit conversion from an enum to an int.

#include <iostream>

enum X {};
bool operator==(X x, int y)
{
    return true;
}

int main()
{
    X x;
    std::cout << std::boolalpha << (x == x+2) << std::endl;
    return 0;
}