help_me_please.rb

class Foo
  class Bar; end
end

anonymous_sub = Class.new(Foo) do
  def check
    Bar
  end
end

class FooSub < Foo
  def check
    Bar
  end
end

FooSub.new.check
# => nil

anonymous_sub.new.check
# => NameError: uninitialized constant Bar