diff --git a/src/Pure/thm_deps.ML b/src/Pure/thm_deps.ML
--- a/src/Pure/thm_deps.ML
+++ b/src/Pure/thm_deps.ML
@@ -1,135 +1,135 @@
 (*  Title:      Pure/thm_deps.ML
     Author:     Stefan Berghofer, TU Muenchen
     Author:     Makarius
 
 Dependencies of theorems wrt. internal derivation.
 *)
 
 signature THM_DEPS =
 sig
   val all_oracles: thm list -> Proofterm.oracle list
   val has_skip_proof: thm list -> bool
   val pretty_thm_oracles: Proof.context -> thm list -> Pretty.T
   val thm_deps: theory -> thm list -> (Proofterm.thm_id * Thm_Name.T) list
   val pretty_thm_deps: theory -> thm list -> Pretty.T
   val unused_thms_cmd: theory list * theory list -> (string * thm) list
 end;
 
 structure Thm_Deps: THM_DEPS =
 struct
 
 (* oracles *)
 
 fun all_oracles thms =
   let
     fun collect (PBody {oracles, thms, ...}) =
       (if null oracles then I else apfst (cons oracles)) #>
       (tap Proofterm.join_thms thms |> fold (fn (i, thm_node) => fn (res, seen) =>
         if Inttab.defined seen i then (res, seen)
         else
           let val body = Future.join (Proofterm.thm_node_body thm_node)
           in collect body (res, Inttab.update (i, ()) seen) end));
     val bodies = map Thm.proof_body_of thms;
   in fold collect bodies ([], Inttab.empty) |> #1 |> Proofterm.unions_oracles end;
 
 fun has_skip_proof thms =
   all_oracles thms |> exists (fn ((name, _), _) => name = \<^oracle_name>\<open>skip_proof\<close>);
 
 fun pretty_thm_oracles ctxt thms =
   let
     val thy = Proof_Context.theory_of ctxt;
     fun prt_ora (name, pos) = Thm.pretty_oracle ctxt name :: Pretty.here pos;
     fun prt_oracle (ora, NONE) = prt_ora ora
       | prt_oracle (ora, SOME prop) =
           prt_ora ora @ [Pretty.str ":", Pretty.brk 1, Syntax.pretty_term_global thy prop];
   in Pretty.big_list "oracles:" (map (Pretty.item o prt_oracle) (all_oracles thms)) end;
 
 
 (* thm_deps *)
 
 fun thm_deps thy =
   let
     val lookup = Global_Theory.lookup_thm_id thy;
     fun deps (i, thm_node) res =
       if Inttab.defined res i then res
       else
         let val thm_id = Proofterm.thm_id (i, thm_node) in
           (case lookup thm_id of
             SOME thm_name =>
               Inttab.update (i, SOME (thm_id, thm_name)) res
           | NONE =>
               Inttab.update (i, NONE) res
               |> fold deps (Proofterm.thm_node_thms thm_node))
         end;
   in
     fn thms =>
       (fold (fold deps o Thm.thm_deps o Thm.transfer thy) thms Inttab.empty, [])
       |-> Inttab.fold_rev (fn (_, SOME entry) => cons entry | _ => I)
   end;
 
 fun pretty_thm_deps thy thms =
   let
     val ctxt = Proof_Context.init_global thy;
     val items =
       map #2 (thm_deps thy thms)
       |> map (fn (name, i) => (Proof_Context.markup_extern_fact ctxt name, i))
       |> sort_by (#2 o #1)
       |> map (fn ((marks, xname), i) =>
           Pretty.item [Pretty.marks_str (marks, Thm_Name.print (xname, i))]);
   in Pretty.big_list ("dependencies: " ^ string_of_int (length items)) items end;
 
 
 (* unused_thms_cmd *)
 
 fun unused_thms_cmd (base_thys, thys) =
   let
     fun add_fact transfer space (name, ths) =
       if exists (fn thy => Global_Theory.defined_fact thy name) base_thys then I
       else
         let val {concealed, group, ...} = Name_Space.the_entry space name in
-          fold_rev (fn th =>
+          fold_rev (transfer #> (fn th =>
             (case Thm.derivation_name th of
               "" => I
-            | a => cons (a, (transfer th, concealed, group)))) ths
+            | a => cons (a, (th, concealed, group))))) ths
         end;
     fun add_facts thy =
       let
         val transfer = Global_Theory.transfer_theories thy;
         val facts = Global_Theory.facts_of thy;
       in Facts.fold_static (add_fact transfer (Facts.space_of facts)) facts end;
 
     val new_thms =
       fold add_facts thys []
       |> sort_distinct (string_ord o apply2 #1);
 
     val used =
       Proofterm.fold_body_thms
         (fn {name = a, ...} => a <> "" ? Symtab.update (a, ()))
         (map Proofterm.strip_thm_body (Thm.proof_bodies_of (map (#1 o #2) new_thms)))
         Symtab.empty;
 
     fun is_unused a = not (Symtab.defined used a);
 
     (*groups containing at least one used theorem*)
     val used_groups = fold (fn (a, (_, _, group)) =>
       if is_unused a then I
       else
         (case group of
           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
         (* FIXME replace by robust treatment of thm groups *)
         Thm.legacy_get_kind th = Thm.theoremK andalso is_unused a
       then
         (case group of
            NONE => ((a, th) :: thms, seen_groups)
          | SOME grp =>
              if Inttab.defined used_groups grp orelse
                Inttab.defined seen_groups grp then q
              else ((a, th) :: thms, Inttab.update (grp, ()) seen_groups))
       else q) new_thms ([], Inttab.empty);
   in rev thms' end;
 
 end;