Using g++ 2.3 on the following

class X {
  public:
     int X1;

     static struct y {
       const int Y1;

       inline y(): Y1(-1) {}

       inline z(X& anX) {anX.X1 = 5;}
    } Y;
 };

I get the message "assignment to non-static member X1 of enclosing
class X" (referring to the statement in X::y::z).

1) Is this a warning or an error?
2) Is this a legitimate message?  The ARM (sec. 9.7) seems to imply
   that what I'm doing is fine...

e-mail appreciated as I don't follow this group.