We can write

instance Bounded a => Bounded (Maybe a) where

  minBound = Nothing

  maxBound = Just maxBound

instance (Bounded a, Bounded b) => Bounded (Either a b) where

  minBound = Left minBound

  maxBound = Right maxBound

While Bounded intentionally does not have an Ord superclass, I think it's worth mentioning that these are the instances that arise naturally from the Ord instances for the types in question.

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