title: Error "Cannot invoke initializer for type 'String' with an argument list of type '(Int64?)'" with nil-coalescing operator
body: <p>I am getting an error "Cannot invoke initializer for type 'String' with an argument list of type '(Int64?)'" with nil-coalescing operator.</p>
  
  <p>There are similar questions on stack<strong>overflow</strong>, but they did not give me the solution I need.</p>
  
  <p>My code with errors in comments:</p>
  
  <pre><code>let cell = tableView.dequeueReusableCell(withIdentifier: "countCell", for: indexPath)
  cell.textLabel?.text = String(detailItem?.count) ?? "1" // Cannot invoke initializer for type 'String' with an argument list of type '(Int64?)'
  
  let cell = tableView.dequeueReusableCell(withIdentifier: "countCell", for: indexPath)
  cell.textLabel?.text = String(Int(detailItem?.count)) ?? "1" // Cannot invoke initializer for type 'Int' with an argument list of type '(Int64?)'
  
  let cell = tableView.dequeueReusableCell(withIdentifier: "countCell", for: indexPath)
  cell.textLabel?.text = String(Int(detailItem!.count)) ?? "1" // Cannot invoke initializer for type 'Int' with an argument list of type '(Int64?)'
  
  let cell = tableView.dequeueReusableCell(withIdentifier: "countCell", for: indexPath)
  cell.textLabel?.text = String(detailItem?.count ?? "1") // Cannot convert value of type 'String' to expected argument type 'Int64'
  </code></pre>