title: what will be returned in this method with using statement?
body: <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>