X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fspecialise%2FSpecConstr.lhs;h=4c0d92756a7dd03a3d55e6c87b05cb69757da5ec;hb=7a88e2da8f9cce37f7d2b6af2f4b5a2a9c97bcb2;hp=ad522e96c832659ff4a045bd66d53e1bcdf85e63;hpb=c9959e41ee1d72aa0ca28d51580f1ad3c06f0e8b;p=ghc-hetmet.git

diff --git a/compiler/specialise/SpecConstr.lhs b/compiler/specialise/SpecConstr.lhs
index ad522e9..4c0d927 100644
--- a/compiler/specialise/SpecConstr.lhs
+++ b/compiler/specialise/SpecConstr.lhs
@@ -50,11 +50,7 @@ import UniqFM
 import MonadUtils
 import Control.Monad	( zipWithM )
 import Data.List
-#if __GLASGOW_HASKELL__ > 609
 import Data.Data        ( Data, Typeable )
-#else
-import Data.Generics    ( Data, Typeable )
-#endif
 \end{code}
 
 -----------------------------------------------------
@@ -1440,11 +1436,18 @@ argToPat env in_scope val_env (Note _ arg) arg_occ
 
 argToPat env in_scope val_env (Let _ arg) arg_occ
   = argToPat env in_scope val_env arg arg_occ
+	-- See Note [Matching lets] in Rule.lhs
 	-- Look through let expressions
-	-- e.g.		f (let v = rhs in \y -> ...v...)
-	-- Here we can specialise for f (\y -> ...)
+	-- e.g.		f (let v = rhs in (v,w))
+	-- Here we can specialise for f (v,w)
 	-- because the rule-matcher will look through the let.
 
+{- Disabled; see Note [Matching cases] in Rule.lhs
+argToPat env in_scope val_env (Case scrut _ _ [(_, _, rhs)]) arg_occ
+  | exprOkForSpeculation scrut	-- See Note [Matching cases] in Rule.hhs
+  = argToPat env in_scope val_env rhs arg_occ
+-}
+
 argToPat env in_scope val_env (Cast arg co) arg_occ
   | not (ignoreType env ty2)
   = do	{ (interesting, arg') <- argToPat env in_scope val_env arg arg_occ