Well, it kinda works in Haskell, but you get weird type signatures. I haven't tried Liquid Haskell but it looks like a potential solution. But you're right. Ev

Well, it kinda works in Haskell, but you get weird type signatures. I haven't tried Liquid Haskell but it looks like a potential solution. But you're right. Even in Haskell, I always write type signatures for functions. It makes type inference debugging easier. But as I understand it, this feature in Ruby is for compilers. It's a compiler's job to translate human-readable (hopefully) source code to an efficient mess of machine code.