- extensions: MagicHash, ExistentialQuantification, Rank2Types,
- ScopedTypeVariables, UnboxedTuples,
- ForeignFunctionInterface, UnliftedFFITypes,
- DeriveDataTypeable, GeneralizedNewtypeDeriving,
- FlexibleInstances, PatternSignatures, StandaloneDeriving,
- PatternGuards, EmptyDataDecls