Static object declaration only causing no error

Why the code is not causing compile error?

 #include<iostream>
 class x{
  private:
   int v;
  public:
   x():v(7){};
 };

class b{
 private:
  static x as;
  int a;
 public:
  b():a(8){};
};
//x b::as;

int main(){
  b g;
  return 0;
 }

Even after commenting the particular line x b::as code works which I think it should as I haven't define/initiate my static object which is necessary. Why is it so?

And what if I initiate non-static object using static object like static x asd; x bv=asd; ?