Could be right. Make a change in one place to see how it behaves, code elsewhere that wouldn't be executed for your test input now doesn't compile - do you get

Could be right. Make a change in one place to see how it behaves, code elsewhere that wouldn't be executed for your test input now doesn't compile - do you get to learn from that experiment now, or do you have to go and placate the compiler temporarily first. For example, making unused function arguments a fatal error would be an easy place to increase iteration time.