each() function is deprecated, use foreach() instead.
-while (list($key, $callback) = each($callbacks)) {
+foreach ($callbacks as $key => $callback) {
// ...
}Configure your rector.php:
<?php
use Rector\Config\RectorConfig;
use Rector\Php72\Rector\While_\WhileEachToForeachRector;
return RectorConfig::configure()
->withRules([
WhileEachToForeachRector::class,
]);