Mostly-fix Trac #2595: updates for existentials

[ghc-hetmet.git] / compiler / deSugar / DsUtils.lhs

diff --git a/compiler/deSugar/DsUtils.lhs b/compiler/deSugar/DsUtils.lhs
index 62328bc..f2609b7 100644 (file)
--- a/compiler/deSugar/DsUtils.lhs
+++ b/compiler/deSugar/DsUtils.lhs
@@ -46,6 +46,7 @@ import {-# SOURCE #-} DsExpr( dsExpr )
 
 import HsSyn
 import TcHsSyn
+import TcType( tcSplitTyConApp )
 import CoreSyn
 import DsMonad
 
@@ -287,7 +288,8 @@ mkCoAlgCaseMatchResult var ty match_alts
     (con1, arg_ids1, match_result1) = ASSERT( notNull match_alts ) head match_alts
     arg_id1    = ASSERT( notNull arg_ids1 ) head arg_ids1
     var_ty      = idType var
-    (tc, ty_args) = splitNewTyConApp var_ty
+    (tc, ty_args) = tcSplitTyConApp var_ty     -- Don't look through newtypes
+                                               -- (not that splitTyConApp does, these days)
     newtype_rhs = unwrapNewTypeBody tc ty_args (Var var)
                
        -- Stuff for data types
@@ -299,11 +301,10 @@ mkCoAlgCaseMatchResult var ty match_alts
              | otherwise
              = CanFail
 
-    wild_var = mkWildId (idType var)
     sorted_alts  = sortWith get_tag match_alts
     get_tag (con, _, _) = dataConTag con
     mk_case fail = do alts <- mapM (mk_alt fail) sorted_alts
-                      return (Case (Var var) wild_var ty (mk_default fail ++ alts))
+                      return (mkWildCase (Var var) (idType var) ty (mk_default fail ++ alts))
 
     mk_alt fail (con, args, MatchResult _ body_fn) = do
           body <- body_fn fail
@@ -350,7 +351,7 @@ mkCoAlgCaseMatchResult var ty match_alts
     mk_parrCase fail = do
       lengthP <- dsLookupGlobalId lengthPName
       alt <- unboxAlt
-      return (Case (len lengthP) (mkWildId intTy) ty [alt])
+      return (mkWildCase (len lengthP) intTy ty [alt])
       where
        elemTy      = case splitTyConApp (idType var) of
                        (_, [elemTy]) -> elemTy
@@ -362,9 +363,8 @@ mkCoAlgCaseMatchResult var ty match_alts
          l      <- newSysLocalDs intPrimTy
          indexP <- dsLookupGlobalId indexPName
          alts   <- mapM (mkAlt indexP) sorted_alts
-         return (DataAlt intDataCon, [l], (Case (Var l) wild ty (dft : alts)))
+         return (DataAlt intDataCon, [l], mkWildCase (Var l) intPrimTy ty (dft : alts))
           where
-           wild = mkWildId intPrimTy
            dft  = (DEFAULT, [], fail)
        --
        -- each alternative matches one array length (corresponding to one