Unserialize issue in php 7

<?php

class Identity
{
    private $role;

    public function __construct($role)
    {
        $this->role = $role;
    }
}

class Entry implements \Serializable
{
    private $identity;

    public function __construct(Identity $identity)
    {
        $this->identity = $identity;
    }

    public function serialize()
    {
        return serialize(array($this->identity));
    }

    public function unserialize($serialized)
    {
        list($this->identity) = unserialize($serialized);
    }
}

$identity = new Identity('test');
$identityRef = &$identity;

$entry1 = new Entry($identity);
$entry2 = new Entry($identityRef);

$serialized = serialize([$entry1, $entry2]);
print_r(unserialize($serialized));