Reference collapsing rules - what does the 3rd rule mean?

So the reference collapsing rules are like:

+------+-----+--------+
| T    | Use | Result |
|------|--------------|
| X&   | T&  | X&     |
| X&   | T&& | X&     |
| X&&  | T&  | X&     |
| X&&  | T&& | X&&    |
+------+-----+--------+.

I'm having a difficulty understanding the 3rd rule. It essentialy says that a reference to a rvalue collapses to a lvalue reference, does it not?

How could you pass a rvalue by reference? The following code is illegal:

int foo(int& i) {
   std::cout << i << std:endl;
}

int main (int argc, char** argv) {
    return foo(43);  // Passing rvalue (i.e T&&)
}

I'm clearing missing something here :) Cheers