001+ Fatal error: Uncaught TypeError: Cannot assign integer to reference of type ?unknown in %s/language013.php:7
002+ Stack trace:
003+ #0 %s/language013.php(22): C1->inc()
004+ #1 {main}
001- 1
002- 2
003- 1
004- 2
005+ thrown in %s/language013.php on line 7