[marcosdumay]

The point of a type system is 100% guarantees. Honestly, if it fails at that, I'm not sure it becomes useful at all for correctness (it may still be useful for operation overloading).

Now, of course, nearly all systems have many properties that you don't want to enforce by the type system. Proofs are hard work, better do them only where it's easiest or really important.

Yet, most times I hear the phrase "static typing zealots", it comes from somebody that does not have experience with a good type system and is thus completely unable to weight off the work of constructing your types and the one of getting enough tests to be sure your program works.