content: {-# LANGUAGE FlexibleInstances #-}
  {-# LANGUAGE FlexibleContexts #-}
  {-# LANGUAGE GADTs #-}
  {-# LANGUAGE GeneralizedNewtypeDeriving #-}
  {-# LANGUAGE MultiParamTypeClasses #-}
  {-# LANGUAGE StandaloneDeriving #-}
  {-# LANGUAGE TypeFamilies #-}
  {-# LANGUAGE UndecidableInstances #-}
  module Control.Arrow.Transformer.Abstract.Error(ErrorT(..),runErrorT) where
  
  import Prelude hiding (id,lookup,(.),read,fail)
  
  import Control.Arrow
  import Control.Arrow.Cont
  import Control.Arrow.Const
  import Control.Arrow.Environment as Env
  import Control.Arrow.Closure as Cls
  import Control.Arrow.Fail
  import Control.Arrow.Trans
  import Control.Arrow.Reader
  import Control.Arrow.State
  import Control.Arrow.Store as Store
  import Control.Arrow.Except as Exc
  import Control.Arrow.Fix
  import Control.Arrow.Order
  import Control.Arrow.Transformer.Kleisli
  import Control.Category
  import Control.Arrow.LetRec
  import Control.Arrow.Fix.Context
  
  import qualified Data.Order as O
  import Data.Abstract.Error
  import Data.Abstract.Widening
  
  import Data.Profunctor
  import Data.Profunctor.Unsafe((.#))
  import Data.Coerce
  
  newtype ErrorT e c x y = ErrorT (KleisliT (Error e) c x y)
    deriving (Profunctor, Category, Arrow, ArrowChoice, ArrowLift, ArrowTrans, ArrowRun,
              ArrowCont, ArrowConst r, ArrowState s, ArrowReader r,
              ArrowEnv var val, ArrowLetRec var val, ArrowClosure expr cls, ArrowStore a b, ArrowCallSite ctx,
              ArrowExcept e', ArrowLowerBounded a)
  
  runErrorT :: ErrorT e c x y -> c x (Error e y)
  runErrorT = coerce
  {-# INLINE runErrorT #-}
  
  instance (ArrowChoice c, Profunctor c) => ArrowFail e (ErrorT e c) where
    type Join x (ErrorT e c) = ()
    fail = lift $ arr Fail
    {-# INLINE fail #-}
  
  instance (ArrowChoice c, ArrowApply c, Profunctor c) => ArrowApply (ErrorT e c) where
    app = lift (app .# first coerce)
    {-# INLINE app #-}
  
  instance (ArrowFix (Underlying (ErrorT e c) x y)) => ArrowFix (ErrorT e c x y) where
    type Fix (ErrorT e c x y) = Fix (Underlying (ErrorT e c) x y)
  
  deriving instance (ArrowChoice c, ArrowComplete (Error e y) c) => ArrowComplete y (ErrorT e c)
  
  instance (O.Complete e, ArrowChoice c, ArrowJoin c) => ArrowJoin (ErrorT e c) where
    joinSecond lub f g = lift $ joinSecond (toJoin2 widening (O.⊔) lub) (Success . f) (unlift g)
    {-# INLINE joinSecond #-}
  