= bindIfaceTyVars tv_bndrs $ \ tyvars -> do
{ tc_name <- lookupIfaceTop occ_name
; rhs_tyki <- tcIfaceType rdr_rhs_ty
- ; let rhs = if isOpen then OpenSynTyCon rhs_tyki
+ ; let rhs = if isOpen then OpenSynTyCon rhs_tyki Nothing
else SynonymTyCon rhs_tyki
; return (ATyCon (buildSynTyCon tc_name tyvars rhs))
}