The article says: "So when you change what + means, it will throw away all those methods it compiled with the old definition. Poof. Gone." Is this enough? What

The article says: "So when you change what + means, it will throw away all those methods it compiled with the old definition. Poof. Gone." Is this enough? What about the function's side effects? If the function changed 1000 variables with the wrong + definition, is it going to roll them back?