Nullability of reference types in type of parameter 'propertyName' of 'IEnumerable ValidatableBase.GetErrors(string propertyName)' doesn't match implicitly implemented member 'IEnumerable INotifyDataErrorInfo.GetErrors(string? propertyName)' (possibly because of nullability attributes).

Nullability of reference types in type of 'event EventHandler<DataErrorsChangedEventArgs> ValidatableBase.ErrorsChanged' doesn't match implicitly implemented member 'event EventHandler<DataErrorsChangedEventArgs>? INotifyDataErrorInfo.ErrorsChanged'.

Non-nullable field 'errors' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field 'status' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Possible null reference return.

Non-nullable event 'ErrorsChanged' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the event as nullable.

Converting null literal or possible null value to non-nullable type.

Nullability of reference types in type of parameter 'sender' of 'void MainWindowViewModel.AddressList_ListChanged(object sender, ListChangedEventArgs e)' doesn't match the target delegate 'ListChangedEventHandler' (possibly because of nullability attributes).

Dereference of a possibly null reference.