code: private function loc(Token $startToken)
      {
          if (empty($this->lexer->options['noLocation'])) {
              return new Location($startToken, $this->lexer->lastToken, $this->lexer->source);
          }
  
          return null;
      }
docs: Returns a location object, used to identify the place in
  the source that created a given parsed object.
  
  @return Location|null