Why can't return an object instance by ref?

[Sam Hu]

Hi,

With below code:
class A
{
}
class B
{
public:
ref A createA() //  q2:without type name A is also OK? 
{
    return new A;//q1
}

}
My questions are:
q1.why this can't work?

q2.I can understand below code works:
A createA(){return new A;}
but why this one also works?
ref createA(){return new A;} // no return type A?


Thanks so much for your help in advance.

Regards,
Sam