Ruby 3 RBS dynamic typing

main.rb_main.rbs

#main.rb
class Super
    def initialize(val)
      @val = val
    end

    def val?
      @val
    end
end

class Test < Super
  def initialize(val, flag: true)
    super(val)
    @flag = flag
  end

  def flag?
    @flag
  end
end

#main.rbs
class Super
    attr_reader val : Integer

    def initialize : (val: Integer) -> void
end

class Test < Super
    attr_reader flag : bool

    def initialize : (val: Integer, ?flag: bool) -> void
    def flag? : () -> bool
end