I'm having fantastic success with a custom IO-like monad that lets me statically verify that my unit test suite is totally side effect free. I don't have to re

I'm having fantastic success with a custom IO-like monad that lets me statically verify that my unit test suite is totally side effect free. I don't have to resort to documentation or code reviews to ensure that my teammates write fast, reliable tests. This isn't possible in a language that doesn't restrict side effects.