dequeueExample3.swift

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

  cell.customLabel.text = "Title"

  return cell
}

// Crashing: fatal error
func tableView(_ tableView: UITableView, 
               cellForRowAt indexPath: IndexPath) -> UITableViewCell {
  guard let cell = tableView.dequeueReusableCell(
    withIdentifier: "Cell", for: indexPath) as? CustomCell else {
    fatalError("The registered type for the cell does not match the casting")
  }

  cell.customLabel.text = "Title"

  return cell
}

// Silent error: not customizing the cell if the cast fails
func tableView(_ tableView: UITableView, 
               cellForRowAt indexPath: IndexPath) -> UITableViewCell {
  let cell = tableView.dequeueReusableCell(
    withIdentifier: "Cell", for: indexPath)

  if let cell = cell as? CustomCell {
    cell.customLabel.text = "Title"
  }

  return cell
}

// Silent error: return a default value for the cell 
// in case the cast fails: an empty cell 
func tableView(_ tableView: UITableView, 
               cellForRowAt indexPath: IndexPath) -> UITableViewCell {
  let cell = tableView.dequeueReusableCell(
    withIdentifier: "Cell", for: indexPath) as? CustomCell

  cell?.customLabel.text = "Title"

  return cell ?? UITableViewCell()
}