why it said no identifier for declarator …

[Jesse Phillips via Digitalmars-d-learn]

I take it the output looks something like this:

     struct S {
         int a;
     }

     S s;
     s.a = 3;

     void main() {
     }

Hope this clears up this next problem. Module scope doesn't get 
to utilize a variable, it can only initialize at compile-time.