use Symfony\Component\EventDispatcher\EventDispatcher;

 final class SomeEventDispatcher extends EventDispatcher
 {
     public function __construct()
     {
         $value = 1000;
+        parent::__construct();
     }
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\Symfony\Symfony43\Rector\ClassMethod\EventDispatcherParentConstructRector;

return RectorConfig::configure()
    ->withRules([
        EventDispatcherParentConstructRector::class,
    ]);

SETS:  symfony/event-dispatcher 4.3 symfony/symfony 4.3