what will be returned in this method with using statement?
<p>what this method will return when the <code>db</code> is null for some reason? compile is fine and there is no <code>return</code> statement outside the <code>using</code> block.</p>

<pre><code>public Guid GetUserId(string username)
    {

        using (AndeDBEntities db = new AndeDBEntities())
        {
            var userId =
                from u in db.Users
                where u.Username == username
                   &amp;&amp; u.Deleted != true
                select new { UserID = u.UserId };
            if (userId == null || userId.Count() == 0) 
                return Guid.Empty;
            else 
                return userId.First().UserID;
        }
    }
</code></pre>
