Fix Trac #2701: make deriving check better for unlifted args

[ghc-hetmet.git] / compiler / typecheck / TcGenDeriv.lhs

diff --git a/compiler/typecheck/TcGenDeriv.lhs b/compiler/typecheck/TcGenDeriv.lhs
index 0eabe32..9826f2f 100644 (file)
--- a/compiler/typecheck/TcGenDeriv.lhs
+++ b/compiler/typecheck/TcGenDeriv.lhs
@@ -688,9 +688,7 @@ gen_Ix_binds loc tycon
     data_con
       =        case tyConSingleDataCon_maybe tycon of -- just checking...
          Nothing -> panic "get_Ix_binds"
-         Just dc | any isUnLiftedType (dataConOrigArgTys dc)
-                 -> pprPanic "Can't derive Ix for a single-constructor type with primitive argument types:" (ppr tycon)
-                 | otherwise -> dc
+         Just dc -> dc
 
     con_arity    = dataConSourceArity data_con
     data_con_RDR = getRdrName data_con
@@ -898,9 +896,8 @@ gen_Read_binds get_fixity loc tycon
     data_con_str con = occNameString (getOccName con)
     
     read_punc c = bindLex (punc_pat c)
-    read_arg a ty 
-       | isUnLiftedType ty = pprPanic "Error in deriving:" (text "Can't read unlifted types yet:" <+> ppr ty)
-       | otherwise = noLoc (mkBindStmt (nlVarPat a) (nlHsVarApps step_RDR [readPrec_RDR]))
+    read_arg a ty = ASSERT( not (isUnLiftedType ty) )
+                    noLoc (mkBindStmt (nlVarPat a) (nlHsVarApps step_RDR [readPrec_RDR]))
     
     read_field lbl a = read_lbl lbl ++
                       [read_punc "=",