I read that as &quot;it amazes me that people aren&#x27;t all using Haskell yet&quot;.<p>Because &#x27;show&#x27; is probably all done for side effects. And then, maybe, Haskell would have caught that, due to the wrong type signature. If called from an otherwise pure function.<p>Most other &quot;strong typed&quot; languages wouldn&#x27;t catch that. But that&#x27;s hardly something type systems solve on their own.