"Automated testing does not have this problem." Good point. I mentioned in another comment here that some languages (like Haskell with its strong, static type

"Automated testing does not have this problem." Good point. I mentioned in another comment here that some languages (like Haskell with its strong, static type system) mitigate this problem. And for languages without static type systems of this nature, automated testing can produce the same effect (which is not to imply that tests for Haskell programs are useless).