RemoveIsArrayOnCollectionRector

Remove if instance of collection on already known Collection type

 use Doctrine\Common\Collections\Collection;

 final class SomeClass
 {
     public ?Collection $items;

     public function someMethod()
     {
-        $items = is_array($this->items) ? $this->items : $this->items->toArray();
+        $items = $this->items->toArray();
     }
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\Doctrine\TypedCollections\Rector\If_\RemoveIsArrayOnCollectionRector;

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