Your Haskell example doesn't actually violate its own type system, though. 1/0 is Fractional or Double or whatever, so it gives Infinity. 1`div`0 is Integer and

Your Haskell example doesn't actually violate its own type system, though. 1/0 is Fractional or Double or whatever, so it gives Infinity. 1`div`0 is Integer and Infinity is not an Integer, so it explodes, instead. Definitely confusing. Perhaps poorly designed. But it's not type-theoretically incorrect. I'm complaining about TypeScript being literally incorrect in its handling of types. Not "strange" or "weird" or "surprising", but incorrect.