无法将PFObject类型的值转换为PFUser

我有一个tableView填充了一个名为matchesResults的数组 . 当您点击单元格时，我想转换到包含该对象详细信息的视图 . 为此，我设置了以下功能：

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath)
    {       
        self.viewUser = matchesResults[indexPath.row] as! PFUser

        self.performSegueWithIdentifier("UserSegue", sender: "self.viewUser")
    }

但是，当我按下tableView中的单元格时，我得到以下错误： Could not cast value of type 'PFObject' to 'PFUser' 在我定义self.viewUser的上面一行 .

如果我尝试将其作为PFObject投射，应用程序将无法运行，我收到错误 Cannot assign a value of type 'PFObject' to a value of type 'PFUser!" .

我该如何解决这个问题？

谢谢！

编辑：使用此查询创建数组（realMatches初始化为 [PFObject] ）：

let userQuery = PFQuery(className: "Match")
            userQuery.whereKey("user1", equalTo: user)

            let userQuery2 = PFQuery(className: "Match")
            userQuery2.whereKey("user2", equalTo: user)

            let currentUserQuery = PFQuery(className: "Match")
            currentUserQuery.whereKey("user1", equalTo: PFUser.currentUser()!)
            currentUserQuery.whereKey("isActive", equalTo: true)

            let currentUserQuery2 = PFQuery(className: "Match")
            currentUserQuery2.whereKey("user2", equalTo: PFUser.currentUser()!)
            currentUserQuery2.whereKey("isActive", equalTo: true)

            let query = PFQuery.orQueryWithSubqueries([userQuery, userQuery2, currentUserQuery, currentUserQuery2])
            query.includeKey("user1")
            query.includeKey("user2")
            query.findObjectsInBackgroundWithBlock{
                (results: [PFObject]?, error: NSError?) -> Void in

                if error != nil {
                    print(error)
                } else {

                    if results != nil {

                        self.matchesResults = results!
                        for result in results!{
                            if result.objectId != self.currentUser!.objectId {
                                self.realMatches.append(result)

编辑2：segue代码：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if (segue.identifier == "UserSegue") {
            let destinationVC = segue.destinationViewController as! UserViewController
            destinationVC.user = self.viewUser as! PFUser
        }
    }
}

当我单击一个单元格以启动segue时，我在 destinationVC.user = self.viewUser as! PFUser 行上收到错误 Could not cast value of type 'PFObject' to 'PFUser' .