`implicit_this_reference_in_initializer` could have an `Add late keyword` fix

[FMorschel]

Consider:

class A {
  final int v;
  final bool isEven = v.isEven; // implicit_this_reference_in_initializer
  A(this.v);
}

This could be fixed by adding the late keyword.

[FMorschel]

Probably turning the field into a getter too. I'll take a look at these cases.

[bwilkerson]

Neither marking the field as late

class A {
  late final int v;
  final bool isEven = v.isEven; // implicit_this_reference_in_initializer
  A(this.v);
}

nor converting it to a getter

class A {
  final int _v;
  final bool isEven = v.isEven; // implicit_this_reference_in_initializer
  A(this._v);
  int get v => _v;
}

causes the error to go away. I don't think either of these is a valid fix.

[FMorschel]

Sorry, I didn't make myself clear. I was suggesting that we make isEven a late field or turn it into a getter, not v.

class A {
  final int v;
  late final bool isEven = v.isEven;
  A(this.v);
}

Or

class A {
  final int v;
  bool get isEven => v.isEven;
  A(this.v);
}

[bwilkerson]

Yes, those would work.

[FMorschel]

@bwilkerson

sdk/pkg/analysis_server/lib/src/services/correction/dart/add_late.dart

Lines 37 to 43 in d56caba

	// TODO(brianwilkerson): Consider converting this into an assist and
	// expand it to support converting `var` to `late` as well as
	// working anywhere a non-late local variableElement or field is selected.
	// } else if (keyword.type == Keyword.VAR) {
	// builder.addFileEdit(file, (builder) {
	// builder.addSimpleReplacement(range.token(keyword), 'late');
	// });

I was working on this and stumbled upon this TODO. I don't think that converting 'var' to 'late' is valid (because of missing_const_final_var_or_type):

class A {
  late v; // missing_const_final_var_or_type
  void foo() {
    late o; // missing_const_final_var_or_type
  }
}

Can I remove this suggestion, or is there some case I can't remember? I've already made this into an assist.

Here is the CL https://dart-review.googlesource.com/c/sdk/+/429081.

[bwilkerson]

I'm not sure what case I was thinking of. Most likely I was just wrong and it doesn't make sense. So, yes, feel free to remove the TODO.