Like tests, types can be more hassle than theyre worth if you dont use them correctly. Before mypy came along I was pretty disciplined at A) testing and B) rut

Like tests, types can be more hassle than theyre worth if you dont use them correctly. Before mypy came along I was pretty disciplined at A) testing and B) ruthlessly clamping down on primitive obsession. I use types a lot now but I didnt see enormous quality or productivity gains when I started using them. I suspect people who let compilers catch their bugs were always A) pretty lax testers and B) probably often let primitive obsession get the better of them. There are only a few types of tests where I think that types actually serve as an appropriate substitute.