Hi @JakubMisek
I found this issue:
/**
*
* @property-read int $code
* @property-write int|BackedEnum $code
*/
<?php
declare(strict_types=1);
namespace Devsense\Builtin\Properties;
use BackedEnum;
final class ClassC {}
$c = new ClassC();
$c->code = 123;

Thank you for the fix.