Why lvalues can be bound to rvalue ref but it cant be done directly? [duplicate]

This question already has an answer here:

• Concise explanation of reference collapsing rules requested: (1) A& & -> A& , (2) A& && -> A& , (3) A&& & -> A& , and (4) A&& && -> A&& 2 answers

I was trying to play with rvalue references and suddenly I discovered something like rvalue reference of lvalue reference ( int& &&) exists but developer cant just write them directly in source.

Explain the error and solution for following code :

int main()
{
    int i=5;
    auto &&irr=i;

    using T=int&;
    T &&irr2=i;

    int& &&irr3=i;  // produces error
    return 0;
}

Thanks in advance...