TypedPropertyFromToManyRelationTypeRector

Complete @var annotations or types based on @ORM\*toMany annotations or attributes

 use Doctrine\ORM\Mapping as ORM;

 class SimpleColumn
 {
     /**
      * @ORM\OneToMany(targetEntity="App\Product")
+     * @var \Doctrine\Common\Collections\Collection<int, \App\Product>
      */
-    private $products;
+    private \Doctrine\Common\Collections\Collection $products;
 }

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\Doctrine\CodeQuality\Rector\Property\TypedPropertyFromToManyRelationTypeRector;

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