Not the OP, but most compilers for languages with static type systems are too slow for my taste. I have a workflow for writing lua programs in which I embed all of my tests in the same file that contains all of the runtime logic. Whenever that file changes, I have a monitor script that runs the program and validates my tests. This process typically happens in less than 20ms, so I've configured my editor to save my lua files whenever I type a single keystroke. It's like having a living REPL session that is persistently stored in the file.

When you develop in this style, you tend not to write type errors because you are constantly validating your program inputs and outputs, which the tight feedback loop encourages. Most statically typed languages have slow compilers. It is not uncommon for an incremental compile to take at least 1s, which is 50-100x slower than what I'm used to. Indeed, I find it distracting when compilation is that slow so with such a language I will still use a monitor script for iteration but I will manually save when I want validation. This means that I am not only getting slower feedback, I am getting less of it, which ultimately makes me less confident in my program. If I were making lots of type errors, maybe it would be worth it to have a type checker, but I'm generally not.