haskell@gentoo.org Gentoo Haskell Enable the use of the `aeson` package. This may be useful for accelerating builds in sandboxes for expert users. Enable the use of the `semigroupoids` package. This may be useful for accelerating builds in sandboxes for expert users. Enable the use of the `semirings` package. This may be useful for accelerating builds in sandboxes for expert users. Enable the use of the `vector` package. This may be useful for accelerating builds in sandboxes for expert users. Include infrastructure for testing class laws of unary type constructors. Include infrastructure for testing class laws of binary type constructors. Disabling `unary-laws` while keeping `binary-laws` enabled is an unsupported configuration. This library provides QuickCheck properties to ensure that typeclass instances adhere to the set of laws that they are supposed to. There are other libraries that do similar things, such as `genvalidity-hspec` and `checkers`. This library differs from other solutions by not introducing any new typeclasses that the user needs to learn. /Note:/ on GHC < 8.5, this library uses the higher-kinded typeclasses ('Data.Functor.Classes.Show1', 'Data.Functor.Classes.Eq1', 'Data.Functor.Classes.Ord1', etc.), but on GHC >= 8.5, it uses `-XQuantifiedConstraints` to express these constraints more cleanly.