A linter rule to recommend "mixing in"

[nate-thegrate]

I think it'd be nice to have a linter rule that recommends using with rather than extends when inheriting from a mixin class.

For example:

class A extends ChangeNotifier {}

class B with ChangeNotifier {}

I believe that B offers improved readability, since it's much clearer that the class could inherit from ChangeNotifier while also extending from something else.

• It gives a better intuition about different ways the class could be restructured in the future.
• If the class is part of a public package, anyone reading it would gain a better intuition about how ChangeNotifier could be used in their own projects.

[lrhn]

If a class can be both extended and mixed in, then presumably the author thinks it's OK to do either.
Otherwise they could just make it a non-class mixin.

But if you want to prefer with over extends, that's obviously your choice. A lint could help you with that.