anchor.diff:      CLASS_BODY;
       CLASS_DECL;
       CONDITION;
  +    DIRECTIVE;
       EXPR;
       EXPR_LIST;
       EXPR_STMT;
  
positive.code:     ;
  
  directiveStatement
      : directive (';'!)?
      ;
  
  directive
  
negative.code:     | enumeration
      | selfReference
      | nameAndTypeArguments
      ;
  
  memberSelector
  