[stank345]

I have experienced the exact same thing in Python and it feels bad to not make changes out of fear of breaking something. So much so that I won't do refactoring on a large codebase written in a dynamic language with not great code coverage (i.e. pretty much every one I've worked on professionally).

This is where static typing can help a _lot_ in my experience. Your types (and your function signatures) are contracts you still need to adhere to after you're done refactoring. Keep making changes until the compiler tells you it's all good and then usually it is.