You have the variance bit totally backwards. Methods are contravariant on their input and covariant on their results. A method which can only feed cats is not a

You have the variance bit totally backwards. Methods are contravariant on their input and covariant on their results. A method which can only feed cats is not a method which can feed all animals. A method which gives me a cat, well, that is certainly a method that gives me an animal. Exceptions are another type of result. Please see https://en.m.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science) https://en.m.wikipedia.org/wiki/Covariance_and_contravarianc... for more info. I agree with your assertion that this is part of what makes explicit throws a pain, though. I hadn't thought about it that way, thanks for the insight.