dequeueExample2.swift

override func viewDidLoad() {
  super.viewDidLoad()

  tableView.register(CustomCell.self, forCellReuseIdentifier: "Cell")
}

func tableView(_ tableView: UITableView, 
               cellForRowAt indexPath: IndexPath) -> UITableViewCell {
  let cell = tableView.dequeueReusableCell(
    withIdentifier: "Cell", for: indexPath) as? CustomCell

  cell.customLabel?.text = "Title" // ERROR: Value of optional type 'CustomCell?' not unwrapped

  return cell // ERROR: Value of optional type 'CustomCell?' not unwrapped
}