How come a non-const reference cannot bind to a temporary object?

Question

Why is it not allowed to get non-const reference to a temporary object, which function getx() returns? Clearly, this is prohibited by C++ Standard but I am in

Answer 1

"It is clear that the temporary object is not constant in the sample above, because calls to non-constant functions are permitted. For instance, ref() could modify the temporary object."

In your example getX() does not return a const X so you are able to call ref() in much the same way as you could call X().ref(). You are returning a non const ref and so can call non const methods, what you can't do is assign the ref to a non const reference.

Along with SadSidos comment this makes your three points incorrect.