1. The argument type 'User Function(User)' can't be assigned to the parameter type 'User Function(User?)'.
2. A value of type 'User?' can't be returned from the method '_userFromFirebaseUser' because it has a return type of 'User'.

CodePudding user response：

Since you might return null from your function, you need to declare your function that null is possible, so instead of:

User _userFromFirebaseUser(auth.User user) {
  ...
}

You have to write it like this:

User? _userFromFirebaseUser(auth.User user) {
  ...
}

Mind the question mark - this essentially means, that this function will either return your User object or null, without the question mark, it always has to be an instance of User

CodePudding user response：

I assume you want _userFromFirebaseUser to return your User model, not auth.User, right?

User _userFromFirebaseUser(auth.User user) {
  return User(uid: user.uid);
}