You may use this one function instead depricated
/**
* Get parameter class
* @param \ReflectionParameter $parameter
* @return \ReflectionClass|null
*/
private function getClass(\ReflectionParameter $parameter):?\ReflectionClass
{
$type = $parameter->getType();
if (!$type || $type->isBuiltin())
return NULL;
// This line triggers autoloader!
if(!class_exists($type->getName()))
return NULL;
return new \ReflectionClass($type->getName());
}