src/Pure/Thy/thm_deps.ML

           NONE => I
         | SOME grp => Inttab.update (grp, ()))) new_thms Inttab.empty;
 
     val (thms', _) = fold (fn (a, (th, concealed, group)) => fn q as (thms, seen_groups) =>
       if not concealed andalso
-        member (op =) [Thm.theoremK, Thm.lemmaK, Thm.corollaryK] (Thm.get_kind th) andalso
+        (* FIXME replace by robust treatment of thm groups *)
+        member (op =) [Thm.theoremK, Thm.lemmaK, Thm.corollaryK] (Thm.legacy_get_kind th) andalso
         is_unused a
       then
         (case group of
            NONE => ((a, th) :: thms, seen_groups)
          | SOME grp =>