Receiving Thread 1: EXC_BAD_ACCESS (code=1, address=0x6b49dedf6a0) Error - swift

Question

I am trying to build a simple To Do app with Core Data.
In CoreData Model, I have created an Entity named "ToDoCoreData". It has one attribute "newToDoItem" type of String.
In CellForRowAt method I'm receiving the following error
Thread 1: EXC_BAD_ACCESS (code=1, address=0x6b49dedf6a0) - but everytime I rerun the app the newly added ToDo appeares in row.
The code is below. Would be glad if someone could help, please.
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var tableView: UITableView!
var toDoList:[ToDoCoreData] = []
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
}
override func viewWillAppear(_ animated: Bool) {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let context = appDelegate.persistentContainer.viewContext
let fetchRequest: NSFetchRequest<ToDoCoreData> = ToDoCoreData.fetchRequest()
do {
toDoList = try context.fetch(fetchRequest)
} catch {
print(error.localizedDescription)
}
}
#IBAction func addNewToDo(_ sender: UIBarButtonItem) {
let ac = UIAlertController(title: "Add Task", message: "add New Task", preferredStyle: .alert)
let ok = UIAlertAction(title: "Add", style: .default) { (action) in
let textField = ac.textFields?[0]
// self.toDoList.insert((textField?.text)!, at: 0)
self.saveToDo(newToDoItem: (textField?.text)!)
self.tableView.reloadData()
}
let cancel = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
ac.addTextField { textfield in
}
ac.addAction(ok)
ac.addAction(cancel)
present(ac, animated: true, completion: nil)
}
func saveToDo(newToDoItem: String) {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let context = appDelegate.persistentContainer.viewContext
let entity = NSEntityDescription.entity(forEntityName: "ToDoCoreData", in: context)
let taskObject = NSManagedObject(entity: entity!, insertInto: context) as! ToDoCoreData
taskObject.newToDoItem = newToDoItem
do {
try context.save()
toDoList.append(taskObject)
print("Success!")
} catch {
print(error.localizedDescription)
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
toDoList.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell", for: indexPath) as! TableViewCell
let toDo = toDoList[indexPath.row]
cell.rowLabel.text = toDo.newToDoItem
return cell
}
}