super.rb

a = Class.new do
  def foo
    yield
  end
end

b = Class.new(a) do
  def foo
    super{
      "b"
    }
  end
end

p b.new.foo{"c"} # => "b"

c = Class.new do
  def foo(&block)
    block.call
  end
end

d = Class.new(c) do
  def foo(&block)
     block = -> { "b" }
    super
  end
end

p d.new.foo{"c"} # => "c"