I get why with covariance I can return a Dog (a Dog is a Mammal), but why does contravariance work the other way? Shouldn't it accept a derived type when it expects a base type? Contravariance is consistent with Postel's Law: […]

And where is now , Master Cope , this your rejecting , expelling , removing , expulsing , exempting , deturbating and thrusting out , of Anatholius , Sother , Dorothea , and other holy saints , out of catalogues , fasts , and calendars?

ignescent stones

This job is difficult because it is so labour-intensive.