haskell-QuickCheck (Automatic testing of Haskell programs) QuickCheck is a library for random testing of program properties. The programmer provides a specification of the program, in the form of properties which functions should satisfy, and QuickCheck then tests that the properties hold in a large number of randomly generated cases. This requires ghc and haskell-mtl. After uninstalling, run this command to unregister the package from the ghc package database: ghc-pkg recache