Wow, you are quick to accuse the community of being a "circle-jerk" even before most people commented. Looking through the other comments on this thread, most a

Wow, you are quick to accuse the community of being a "circle-jerk" even before most people commented. Looking through the other comments on this thread, most are either against the practice or qualify it. And the qualification is completely reasonable--given sufficiently general types, the space of possible implementations becomes very small which means you are increasingly likely to be correct just if your code typechecks. The article never claims you can always use the type system in place of tests. It doesn't even claim that it is a reasonable practice. The only thing it says is that the author did rely on the type system and that he thinks it is reasonable given sufficiently polymorphic types. In short, you're knocking down a straw man and using it to accuse the entire community of being an arroganet circle-jerk.