Can self ever be false or nil?

Question

Can self ever evaluate to false or nil?

For example...

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class FooBar

  ...

  def check_this
    self && check_something_else
  end
end

Is the self && in this conditional necessary?

Answer 1

Yes. Remember everything in Ruby is an object so self is falsy for false and nil:

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nil.instance_eval { self }  # => nil
false.instance_eval { self }  # => false