> "wrong type" I find that people have very different understandings of what "wrong type" means. If you restrict yourself to places where python or js actuall

> "wrong type" I find that people have very different understandings of what "wrong type" means. If you restrict yourself to places where python or js actually mention type in the error messages, that misses a whole lot of things that basic use of a simple type system would catch, much less skilled use of a sophisticated type system. There's an example I give - admittedly tangential given that it does not replace (and could not be replaced by) unit tests, but hopefully giving some insight into the range of what's possible: I once used C's type system to catch "you called this function from the wrong thread" at compile time, converting subtle runtime failures or meaningful runtime overhead into "you can't call this here, dummy" before running anything. This was hugely helpful as requirements evolved and I found myself moving large pieces of functionality between threads. I don't think this clearly resolves the broader discussion; static type checking is a tool and its applicability may well depend on the problems at hand, the language in question, and the developers involved; I think how it should be applied certainly depends on these things. But I think it is too often dismissed based on an overly narrow understanding of what a "type error" can be.