Storing the hashCode about equatable

[FaFre]

I created a package doing exactly that, a couple of months back: https://github.com/FaFre/fast_equatable maybe you can find some inspirations in there.

[felangel]

By adding a mutable property on EquatableMixin, all instances would no longer be immutable.

For example:

import 'package:meta/meta.dart';

mixin EquatableMixin on Object {
  int? _hashCode;
}

@immutable
class Person with EquatableMixin {}

The above code will result in a warning because Person should be immutable but has non-final fields:

[MelbourneDeveloper]

@felangel I don't think anything can be done to fully satisfy the immutable requirement for the mixin.

There would be a similar issue with the Equatable class. Technically this is still immutable:

But, the class loses the const constructor. Still, there is something unwholesome about repeatedly hashing data that doesn't change.