VSTA, not defined in ETL

    Consider a  static access to  `f' a C external routine
    or a .NET static  external of a class `C'. The call is
    valid  if and  only if it  satisfies the following two
    conditions:

        1 `C' is not NONE

        2 `f' is an external routine without assertions, a
          .NET static external or a constant.