Calling nested function before declaration

[Jonathan]

This code fails to compile: ("undefined identifier fun")
void main() {
     fun();
     void fun() {}
}

Having the call after the declaration works:
void main() {
     void fun() {}
     fun();
}

Is this how it is intended to work?

It seems goofy that this works:
void main() {
     void fun2() {}
     void fun() {
          fun2()
     }
     fun();
}

But this fails to compile: ("undefined identifier fun2")
void main() {
     void fun() {
          fun2()
     }
     void fun2() {}
     fun();
}

What if I wanted this?
void main() {
     void fun2() {fun();}
     void fun() {fun2();}
     fun();
}

I can't see how the current behavior is at all better or to be 
preferred unless it is faster to compile?  What is the reason for 
it being how it is?