I like Ruby for prototyping and quick throwaway scrips. I can write code really fast in it. Still my favorite language. But reading unfamiliar code or cooperating with others is hard. This is a good step forward in that direction.

Not in the source code itself, it will be in separate files according to Matt. If you want it in the source code you can use Sorbet today.

Sorbet syntax is like a hack bolted on... I'm not really a fan of it.

Yeah, it's limited by being a library instead of being part of the language itself.