module Wakame.Lacks where import Prelude import Data.Type.Equality import GHC.TypeLits import Wakame.Row (FIELD) -- | Typeclass to constrain not to have a certain key class Lacks (k :: Symbol) (r :: [FIELD]) instance Lacks k '[] instance (Lacks k r, KnownSymbol k', (k == k') ~ 'False) => Lacks k ('(k', a) ': r)