docs: public IsNullValue markInformationAsComingFromFieldValue(XField field) {
          if (getBaseKind() == NO_KABOOM_NN) {
              return new IsNullValue(kind | FIELD_VAL, locationOfKaBoom);
          }
          return instanceByFlagsList[(getFlags() | FIELD_VAL) >> FLAG_SHIFT][getBaseKind()];
      }