@hackage derivingvia-extras0.1.0.0

Includes various functionality to use with DerivingVia.

-- >> alice = User "Alice" 50 0xDEADBEAF
-- >> bob   = User "Bob"   20 0xDEADBEAF
-- >>
-- >> alice == bob
-- True
-- >> hash alice == hash bob
-- True
data User = User
  { name   :: String
  , age    :: Int
  , userID :: Integer
  }
  deriving (Eq, Ord, Hashable)
  via User `On` "userID"