Yes, I had the same question and test in a Pry session and it seems to work
(with 2.0.0, haven't tested with 1.9.3). With the following example:

```ruby
class Foo
  def bar(baz = nil)
    puts baz.class.to_s
  end
end

class Bar < Foo
  def bar(baz = nil)
    baz = "Foo"
    super
  end
end

Bar.new.bar # => String
Foo.new.bar # => NilClass
````