Hi all, Found myself puzzled the other day when I wanted an (Enum a, Enum b) => Enum (a, b) instance, and was distraught that it didn't exist. The following is a reasonable implementation: instance (Bounded b, Enum a, Enum b) => Enum (a, b) where fromEnum (a, b) = (fromEnum (maxBound @b) + 1) * fromEnum a + fromEnum b toEnum n = let bound = fromEnum (maxBound @b) + 1 b = n `rem` bound a = n `div` bound in (toEnum a, toEnum b) And, while we're at it, might as well add canonical instances for Either: instance (Bounded a, Bounded b) => Bounded (Either a b) where minBound = Left minBound maxBound = Right maxBound instance (Bounded a, Enum a, Enum b) => Enum (Either a b) where toEnum i = let bound = fromEnum (maxBound @a) + 1 in case i < bound of True -> Left $ toEnum i False -> Right $ toEnum $ i - bound fromEnum (Left a) = fromEnum a fromEnum (Right b) = fromEnum b + fromEnum (maxBound @a) + 1 Are there any reasons these instances are missing from base? Cheers, Sandy