I've come to think that adding halfway-typing to languages designed from the start to be dynamic is mostly not worth the bother. It may help a little bit sometimes, but there's always going to be holes. If you really want strong typing, it's better IMO to bite the bullet and move to a language designed for it. Let Ruby be Ruby, ditto Python, Javascript etc. Pick up some JVM, .NET, Rust, Go, etc if you really want strong types.