@@ -4,6 +4,7 @@
4{-# LANGUAGE LambdaCase #-}
4{-# LANGUAGE LambdaCase #-}
5{-# LANGUAGE RankNTypes #-}
5{-# LANGUAGE RankNTypes #-}
6{-# LANGUAGE TypeFamilies #-}
6{-# LANGUAGE TypeFamilies #-}
7+{-# LANGUAGE UndecidableInstances #-}
8import Control.Lens
9import Control.Lens
9import Control.Monad.Fix
10import Control.Monad.Fix