For "Haskell-in-practice", incomplete pattern matching isn't an issue - there's a warning for that, you should have it on, and you should have it error. `undef

For "Haskell-in-practice", incomplete pattern matching isn't an issue - there's a warning for that, you should have it on, and you should have it error. `undefined` is more of an issue, although easy to exclude with code review - relying on habits isn't great but especially when the habits are this simple it's not a problem in practice. That said, Haskell still isn't actually an example, chiefly because exceptions can be thrown by any code, and are reasonably often used in practice.