Why is `self` needed inside this instance method?

Question

Going through Well Grounded Rubyist.

class Car
  @@cars = {}
  attr_reader :make
  def make_mates
    @@cars[self.make]
  end
  ...
end

Why do we need self in the make_mates instance method? When I run the code without self, it works the same.

Answer 1

You don't need it in that case.

You only need to refer to an attribute with self if you're assigning to it, to distinguish it from assigning to a local.