bugs

[ghc-hetmet.git] / compiler / basicTypes / MkId.lhs

diff --git a/compiler/basicTypes/MkId.lhs b/compiler/basicTypes/MkId.lhs
index 33482fe..bc45f52 100644 (file)
--- a/compiler/basicTypes/MkId.lhs
+++ b/compiler/basicTypes/MkId.lhs
@@ -316,7 +316,7 @@ mkDataConIds wrap_name wkr_name data_con
                        Case (Var arg) arg result_ty [(DEFAULT,[], body i (arg:rep_args))]
 
                MarkedUnboxed
-                  -> case splitProductType "do_unbox" (idType arg) of
+                  ->case splitProductType "do_unbox" (idType arg) of
                           (tycon, tycon_args, con, tys) ->
                                   Case (Var arg) arg result_ty  
                                        [(DataAlt con, 
@@ -530,7 +530,7 @@ mkRecordSelId tycon field_label
        -- NB: A newtype always has a vanilla DataCon; no existentials etc
        --     res_tys will simply be the dataConUnivTyVars
     sel_body | isNewTyCon tycon = unwrapNewTypeBody tycon res_tys (Var data_id)
-            | otherwise        = Case (Var data_id) data_id field_tau (default_alt ++ the_alts)
+            | otherwise        = Case (Var data_id) data_id field_ty (default_alt ++ the_alts)
 
     mk_result poly_result = mkVarApps (mkVarApps poly_result field_tyvars) field_dict_ids
        -- We pull the field lambdas to the top, so we need to 
@@ -709,35 +709,23 @@ wrapNewTypeBody :: TyCon -> [Type] -> CoreExpr -> CoreExpr
 -- body of the wrapper, namely
 --     e `cast` CoT [a]
 --
--- For non-recursive newtypes, GHC currently treats them like type
--- synonyms, so no cast is necessary.  This function is the only
--- place in the compiler that generates 
+-- If a coercion constructor is prodivided in the newtype, then we use
+-- it, otherwise the wrap/unwrap are both no-ops 
 --
 wrapNewTypeBody tycon args result_expr
---  | isRecursiveTyCon tycon   -- Recursive case; use a coerce
-  = Cast result_expr co
---  | otherwise
---  = result_expr
-  where
-    co = mkTyConApp (newTyConCo tycon) args
+  | Just co_con <- newTyConCo tycon
+  = Cast result_expr (mkTyConApp co_con args)
+  | otherwise
+  = result_expr
 
 unwrapNewTypeBody :: TyCon -> [Type] -> CoreExpr -> CoreExpr
 unwrapNewTypeBody tycon args result_expr
---  | isRecursiveTyCon tycon   -- Recursive case; use a coerce
-  = Cast result_expr sym_co
---  | otherwise
---  = result_expr
-  where
-    sym_co = mkSymCoercion co
-    co     = mkTyConApp (newTyConCo tycon) args
-
--- Old Definition of mkNewTypeBody
--- Used for both wrapping and unwrapping
---mkNewTypeBody tycon result_ty result_expr
---  | isRecursiveTyCon tycon   -- Recursive case; use a coerce
---  = Note (Coerce result_ty (exprType result_expr)) result_expr
---  | otherwise                        -- Normal case
---  = result_expr
+  | Just co_con <- newTyConCo tycon
+  = Cast result_expr (mkSymCoercion (mkTyConApp co_con args))
+  | otherwise
+  = result_expr
+
+
 \end{code}