Lowtype: Elegant Types in Ruby(codeberg.org)

    def method(thing: String | "default value")

     "-> (#{method_node.parameters.slice}) {}"

    class MyClass
      include LowType
      class String; end
      def say_hello(greeting: String); end
    end

    MyClass.new.say_hello(greeting: "hello")

    class MyClass
      include LowType
      class String; end
      def say_hello(greeting: MyClass::String); end
    end

    MyClass.new.say_hello(greeting: "hello") # => ArgumentTypeError