[commit: base] master: Add dataCast* definitions to Ptr/Array Data instances; fixes #7256 (151c2fc)

[Ian Lynagh]

Repository : ssh://darcs.haskell.org//srv/darcs/packages/base

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/151c2fc732beeddf0306af0d0b374e3029aea49e

>---------------------------------------------------------------

commit 151c2fc732beeddf0306af0d0b374e3029aea49e
Author: Ian Lynagh <ian at well-typed.com>
Date:   Fri Nov 30 13:18:41 2012 +0000

    Add dataCast* definitions to Ptr/Array Data instances; fixes #7256
    
    Patch from dreixel.

>---------------------------------------------------------------

 Data/Data.hs |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Data/Data.hs b/Data/Data.hs
index 06f5732..d961086 100644
--- a/Data/Data.hs
+++ b/Data/Data.hs
@@ -1275,27 +1275,27 @@ instance (Data a, Data b, Data c, Data d, Data e, Data f, Data g)
 
 ------------------------------------------------------------------------------
 
-instance Typeable a => Data (Ptr a) where
+instance (Data a, Typeable a) => Data (Ptr a) where
   toConstr _   = error "Data.Data.toConstr(Ptr)"
   gunfold _ _  = error "Data.Data.gunfold(Ptr)"
   dataTypeOf _ = mkNoRepType "GHC.Ptr.Ptr"
-
+  dataCast1 x  = gcast1 x
 
 ------------------------------------------------------------------------------
 
-instance Typeable a => Data (ForeignPtr a) where
+instance (Data a, Typeable a) => Data (ForeignPtr a) where
   toConstr _   = error "Data.Data.toConstr(ForeignPtr)"
   gunfold _ _  = error "Data.Data.gunfold(ForeignPtr)"
   dataTypeOf _ = mkNoRepType "GHC.ForeignPtr.ForeignPtr"
-
+  dataCast1 x  = gcast1 x
 
 ------------------------------------------------------------------------------
 -- The Data instance for Array preserves data abstraction at the cost of 
 -- inefficiency. We omit reflection services for the sake of data abstraction.
-instance (Typeable a, Data b, Ix a) => Data (Array a b)
+instance (Typeable a, Data a, Data b, Ix a) => Data (Array a b)
  where
   gfoldl f z a = z (listArray (bounds a)) `f` (elems a)
   toConstr _   = error "Data.Data.toConstr(Array)"
   gunfold _ _  = error "Data.Data.gunfold(Array)"
   dataTypeOf _ = mkNoRepType "Data.Array.Array"
-
+  dataCast2 x  = gcast2 x