+ // XXX: This method is responsible for reading realsymbol
+ // and possymbol objects too. But
+ // basic::operator=(const basic& other)
+ // resets status_flags::evaluated if other and *this are
+ // of different types. Usually this is a good idea, but
+ // doing this for symbols is wrong (for one, nothing is
+ // going to set status_flags::evaluated, evaluation will
+ // loop forever). Therefore we need to restore flags.
+ setflag(status_flags::evaluated | status_flags::expanded);