let cons IfaceData{ifName,ifCons} = Just (ifName,con)
          where con = case ifCons of
                  IfDataTyCon xs -> map ifConName xs
        cons _ = Nothing
    liftIO $ hPutStrLn stderr $ showSDocDebug (hsc_dflags session) $ ppr $ mapMaybe (cons . snd) $  mi_decls iface