content: {-# LANGUAGE Trustworthy #-}
  {-# LANGUAGE CPP
             , NoImplicitPrelude
             , Rank2Types
             , ExistentialQuantification
    #-}
  
  -----------------------------------------------------------------------------
  -- |
  -- Module      :  GHC.Desugar
  -- Copyright   :  (c) The University of Glasgow, 2007
  -- License     :  see libraries/base/LICENSE
  -- 
  -- Maintainer  :  cvs-ghc@haskell.org
  -- Stability   :  internal
  -- Portability :  non-portable (GHC extensions)
  --
  -- Support code for desugaring in GHC
  -- 
  -----------------------------------------------------------------------------
  
  -- #hide
  module GHC.Desugar ((>>>), AnnotationWrapper(..), toAnnotationWrapper) where
  
  import Control.Arrow    (Arrow(..))
  import Control.Category ((.))
  import Data.Data        (Data)
  
  -- A version of Control.Category.>>> overloaded on Arrow
  #ifndef __HADDOCK__
  (>>>) :: forall arr. Arrow arr => forall a b c. arr a b -> arr b c -> arr a c
  #endif
  -- NB: the type of this function is the "shape" that GHC expects
  --     in tcInstClassOp.  So don't put all the foralls at the front!  
  --     Yes, this is a bit grotesque, but heck it works and the whole
  --     arrows stuff needs reworking anyway!
  f >>> g = g . f
  
  -- A wrapper data type that lets the typechecker get at the appropriate dictionaries for an annotation
  data AnnotationWrapper = forall a. (Data a) => AnnotationWrapper a
  
  toAnnotationWrapper :: (Data a) => a -> AnnotationWrapper
  toAnnotationWrapper what = AnnotationWrapper what
  
  