"protected" is not implemented

[lth]

Consider:

class C {
    protected var v = 10;
}
class D extends C {
    function f() {
        print(v);
    }
}
(new D).f()

Loading this results in an error:

[locn] builtins/Error.es:83.47-83.47
[stack] [f()]
**ERROR** EvalError: uncaught exception:
  ReferenceError: unresolved lexical reference
  {multiname: [ns private '[ns public '']::D ']::v
              [ns public '']::v
              [ns internal '']::v }
  (near builtins/Error.es:83.47-83.47)