Comparing to Python and Javascript, referencing an unused name in source without reaching it in your execution path will not cause an error. a=4 3+a 3

Comparing to Python and Javascript, referencing an unused name in source without reaching it in your execution path will not cause an error. a=4 3+a 3+a or 3+b in a strongly-typed language, that would break compilation. So, Java and C will not compile those, either, but the article doesn't go into other cases where Haskell types are more useful for preventing various errors, such as Data.Result, which can either be a result of the type you expect or an error type, and which the compiler requires you to handle both cases. I think the write up would have benefited from some of the more advanced cases like this.