In Ruby you get nothing like that, all your function arguments are just variable names. This increases testing friction a lot. I've been all over the spectrum: from PHP and Ruby through Elixir (combining best of static and dynamic types IMO, though still flawed) to Golang and finally to Rust which is super strict. To me Elixir and Golang are close to perfect. Rust takes it too far and development velocity can suffer a lot until you become an expert (which can take quite a while).

Plug and play is nice but my opinion remains that it's oversold. Quickly whipping out prototypes is not the only virtue of a programming language (though technically that's a feature of Rails, Ruby's killer app, and not of Ruby itself).