Quick iteration on concepts is actually helped by not having to do extensive testing & maintenance work to keep your system from 500ing, which a static type sys

Quick iteration on concepts is actually helped by not having to do extensive testing & maintenance work to keep your system from 500ing, which a static type system can help you do. The fact that dynamic languages don't care about your bugs is actually a hindrance. What dynamic languages have as an advantage is that they allow you to more readily change your system as your understanding of the requirements change. This is where static type systems have traditionally been very weak - they create roadblocks for evolutionary change. What would be great is a type system which catches your bugs but doesn't block you from evolving. I actually think Rust's use of type class polymorphism ("traits") goes a long way toward that goal, once you learn it.