From: Manuel M T Chakravarty <chak@cse.unsw.edu.au>
Date: Wed, 20 Sep 2006 17:56:32 +0000 (+0000)
Subject: fix default case filling-in for GADTs
X-Git-Tag: After_FC_branch_merge~67
X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=8912a05e1bcc30c7e8e5e017d9cf10176076f141

fix default case filling-in for GADTs
Mon Sep 18 17:04:19 EDT 2006  Manuel M T Chakravarty <chak@cse.unsw.edu.au>
  * fix default case filling-in for GADTs
  Sun Aug  6 20:09:06 EDT 2006  Manuel M T Chakravarty <chak@cse.unsw.edu.au>
    * fix default case filling-in for GADTs
    Fri Jul 28 13:19:40 EDT 2006  kevind@bu.edu
---

diff --git a/compiler/basicTypes/MkId.lhs b/compiler/basicTypes/MkId.lhs
index f912731..de8db07 100644
--- a/compiler/basicTypes/MkId.lhs
+++ b/compiler/basicTypes/MkId.lhs
@@ -474,10 +474,6 @@ mkRecordSelId tycon field_label
 
     (field_tyvars,pre_field_theta,field_tau) = tcSplitSigmaTy field_ty
   
-    mk_co_var k  = mkWildCoVar k
-    eq_vars      = map (mk_co_var . mkPredTy)
-                       (filter isEqPred pre_field_theta)
-
     field_theta  = filter (not . isEqPred) pre_field_theta
     field_dict_tys			 = mkPredTys field_theta
     n_field_dict_tys			 = length field_dict_tys
diff --git a/compiler/simplCore/SimplUtils.lhs b/compiler/simplCore/SimplUtils.lhs
index 235cdfe..ebe4083 100644
--- a/compiler/simplCore/SimplUtils.lhs
+++ b/compiler/simplCore/SimplUtils.lhs
@@ -1139,28 +1139,6 @@ tryRhsTyLam env tyvars body 		-- Only does something if there's a let
 %*									*
 %************************************************************************
 
-\begin{code}
-mkDataConAlt :: DataCon -> [OutType] -> InExpr -> SimplM InAlt
--- Make a data-constructor alternative to replace the DEFAULT case
--- NB: there's something a bit bogus here, because we put OutTypes into an InAlt
-mkDataConAlt con inst_tys rhs
-  = ASSERT(not (isNewTyCon (dataConTyCon con)))
-    do 	{ tv_uniqs <- getUniquesSmpl 
-	; arg_uniqs <- getUniquesSmpl
-	; let tv_bndrs  = zipWith mk_tv_bndr (dataConExTyVars con) tv_uniqs
-	      arg_tys   = dataConInstArgTys con (inst_tys ++ mkTyVarTys tv_bndrs)
-	      arg_bndrs = zipWith mk_arg arg_tys arg_uniqs
-	; return (DataAlt con, tv_bndrs ++ arg_bndrs, rhs) }
-  where
-    mk_arg arg_ty uniq	-- Equality predicates get a TyVar
-			-- while dictionaries and others get an Id
-      | isEqPredTy arg_ty = mk_tv arg_ty uniq
-      | otherwise	  = mk_id arg_ty uniq
-
-    mk_tv_bndr tv uniq = mk_tv (tyVarKind tv) uniq
-    mk_tv kind uniq = mkTyVar (mkSysTvName uniq FSLIT("t")) kind
-    mk_id ty   uniq = mkSysLocal FSLIT("a") uniq ty
-\end{code}
 
 mkCase puts a case expression back together, trying various transformations first.
 
diff --git a/compiler/simplCore/Simplify.lhs b/compiler/simplCore/Simplify.lhs
index e2435c2..0dde73d 100644
--- a/compiler/simplCore/Simplify.lhs
+++ b/compiler/simplCore/Simplify.lhs
@@ -1553,7 +1553,10 @@ simplDefault env case_bndr' imposs_cons cont (Just rhs)
 
 	[con] -> 	-- It matches exactly one constructor, so fill it in
 		 do { tick (FillInCaseDefault case_bndr')
-		    ; con_alt <- mkDataConAlt con inst_tys rhs
+                    ; us <- getUniquesSmpl
+                    ; let (ex_tvs, co_tvs, arg_ids) =
+                              dataConInstPat us con inst_tys
+                    ; let con_alt = (DataAlt con, ex_tvs ++ co_tvs ++ arg_ids, rhs)
 		    ; Just (_, alt') <- simplAlt env [] case_bndr' cont con_alt
 			-- The simplAlt must succeed with Just because we have
 			-- already filtered out construtors that can't match