I think what the most import for refactoring, is about runtime. When you get a totally unfamiliar code base, only if you can run it over and over, or at least

I think what the most import for refactoring, is about runtime. When you get a totally unfamiliar code base, only if you can run it over and over, or at least run the tests over and over, then you can talk about the refactoring. If you can't, the refactoring is almost impossible, not matter how strong the type system is. For an argument which require type of string, the behavior could be unexpected if you just give it a string.