diff --git a/src/HOL/Tools/Sledgehammer/sledgehammer_fact.ML b/src/HOL/Tools/Sledgehammer/sledgehammer_fact.ML
--- a/src/HOL/Tools/Sledgehammer/sledgehammer_fact.ML
+++ b/src/HOL/Tools/Sledgehammer/sledgehammer_fact.ML
@@ -1,572 +1,572 @@
 (*  Title:      HOL/Tools/Sledgehammer/sledgehammer_fact.ML
     Author:     Jia Meng, Cambridge University Computer Laboratory and NICTA
     Author:     Jasmin Blanchette, TU Muenchen
 
 Sledgehammer fact handling.
 *)
 
 signature SLEDGEHAMMER_FACT =
 sig
   type status = ATP_Problem_Generate.status
   type stature = ATP_Problem_Generate.stature
 
   type lazy_fact = ((unit -> string) * stature) * thm
   type fact = (string * stature) * thm
 
   type fact_override =
     {add : (Facts.ref * Token.src list) list,
      del : (Facts.ref * Token.src list) list,
      only : bool}
 
   val no_fact_override : fact_override
 
   val fact_of_ref : Proof.context -> Keyword.keywords -> thm list -> status Termtab.table ->
     Facts.ref * Token.src list -> ((string * stature) * thm) list
   val cartouche_thm : Proof.context -> thm -> string
   val is_blacklisted_or_something : string -> bool
   val clasimpset_rule_table_of : Proof.context -> status Termtab.table
   val build_name_tables : (thm -> string) -> ('a * thm) list ->
     string Symtab.table * string Symtab.table
   val fact_distinct : (term * term -> bool) -> ('a * thm) list -> ('a * thm) list
   val instantiate_inducts : Proof.context -> term list -> term ->
     (((unit -> string) * 'a) * thm) list -> (((unit -> string) * 'a) * thm) list
   val fact_of_lazy_fact : lazy_fact -> fact
   val is_useful_unnamed_local_fact : Proof.context -> thm -> bool
 
   val all_facts : Proof.context -> bool -> Keyword.keywords -> thm list -> thm list ->
     status Termtab.table -> lazy_fact list
   val nearly_all_facts : Proof.context -> bool -> fact_override -> Keyword.keywords ->
     status Termtab.table -> thm list -> term list -> term -> lazy_fact list
   val nearly_all_facts_of_context : Proof.context -> bool -> fact_override -> thm list ->
     term list -> term -> lazy_fact list
   val drop_duplicate_facts : lazy_fact list -> lazy_fact list
 end;
 
 structure Sledgehammer_Fact : SLEDGEHAMMER_FACT =
 struct
 
 open ATP_Util
 open ATP_Problem_Generate
 open Sledgehammer_Util
 
 type lazy_fact = ((unit -> string) * stature) * thm
 type fact = (string * stature) * thm
 
 type fact_override =
   {add : (Facts.ref * Token.src list) list,
    del : (Facts.ref * Token.src list) list,
    only : bool}
 
 val local_thisN = Long_Name.localN ^ Long_Name.separator ^ Auto_Bind.thisN
 
 (* gracefully handle huge background theories *)
 val max_facts_for_duplicates = 50000
 val max_facts_for_complex_check = 25000
 val max_simps_for_clasimpset = 10000
 
 val no_fact_override = {add = [], del = [], only = false}
 
 fun needs_quoting keywords s =
   Keyword.is_literal keywords s orelse
   exists (not o Symbol_Pos.is_identifier) (Long_Name.explode s)
 
 fun make_name keywords multi j name =
   (name |> needs_quoting keywords name ? quote) ^
   (if multi then "(" ^ string_of_int j ^ ")" else "")
 
 fun explode_interval _ (Facts.FromTo (i, j)) = i upto j
   | explode_interval max (Facts.From i) = i upto i + max - 1
   | explode_interval _ (Facts.Single i) = [i]
 
 fun is_rec_eq lhs = Term.exists_subterm (curry (op =) (head_of lhs))
 
 fun is_rec_def \<^Const_>\<open>Trueprop for t\<close> = is_rec_def t
   | is_rec_def \<^Const_>\<open>Pure.imp for _ t2\<close> = is_rec_def t2
   | is_rec_def \<^Const_>\<open>Pure.eq _ for t1 t2\<close> = is_rec_eq t1 t2
   | is_rec_def \<^Const_>\<open>HOL.eq _ for t1 t2\<close> = is_rec_eq t1 t2
   | is_rec_def _ = false
 
 fun is_assum assms th = exists (fn ct => Thm.prop_of th aconv Thm.term_of ct) assms
 fun is_chained chained = member Thm.eq_thm_prop chained
 
 fun scope_of_thm global assms chained th =
   if is_chained chained th then Chained
   else if global then Global
   else if is_assum assms th then Assum
   else Local
 
 val may_be_induction =
   exists_subterm (fn Var (_, Type (\<^type_name>\<open>fun\<close>, [_, T])) => body_type T = \<^typ>\<open>bool\<close>
     | _ => false)
 
 (* TODO: get rid of *)
 fun normalize_vars t =
   let
     fun normT (Type (s, Ts)) = fold_map normT Ts #>> curry Type s
       | normT (TVar (z as (_, S))) =
         (fn ((knownT, nT), accum) =>
             (case find_index (equal z) knownT of
               ~1 => (TVar ((Name.uu, nT), S), ((z :: knownT, nT + 1), accum))
             | j => (TVar ((Name.uu, nT - j - 1), S), ((knownT, nT), accum))))
       | normT (T as TFree _) = pair T
 
     fun norm (t $ u) = norm t ##>> norm u #>> op $
       | norm (Const (s, T)) = normT T #>> curry Const s
       | norm (Var (z as (_, T))) = normT T
         #> (fn (T, (accumT, (known, n))) =>
           (case find_index (equal z) known of
             ~1 => (Var ((Name.uu, n), T), (accumT, (z :: known, n + 1)))
           | j => (Var ((Name.uu, n - j - 1), T), (accumT, (known, n)))))
       | norm (Abs (_, T, t)) = norm t ##>> normT T #>> (fn (t, T) => Abs (Name.uu, T, t))
       | norm (Bound j) = pair (Bound j)
       | norm (Free (s, T)) = normT T #>> curry Free s
   in fst (norm t (([], 0), ([], 0))) end
 
 fun status_of_thm css name th =
   if Termtab.is_empty css then
     General
   else
     let val t = Thm.prop_of th in
       (* FIXME: use structured name *)
       if String.isSubstring ".induct" name andalso may_be_induction t then
         Induction
       else
         let val t = normalize_vars t in
           (case Termtab.lookup css t of
             SOME status => status
           | NONE =>
             let val concl = Logic.strip_imp_concl t in
               (case try (HOLogic.dest_eq o HOLogic.dest_Trueprop) concl of
                 SOME lrhss =>
                 let
                   val prems = Logic.strip_imp_prems t
                   val t' = Logic.list_implies (prems, Logic.mk_equals lrhss)
                 in
                   Termtab.lookup css t' |> the_default General
                 end
               | NONE => General)
             end)
         end
     end
 
 fun stature_of_thm global assms chained css name th =
   (scope_of_thm global assms chained th, status_of_thm css name th)
 
 fun fact_of_ref ctxt keywords chained css (xthm as (xref, args)) =
   let
     val ths = Attrib.eval_thms ctxt [xthm]
     val bracket =
       implode (map (enclose "[" "]" o Pretty.unformatted_string_of o Token.pretty_src ctxt) args)
 
     fun nth_name j =
       (case xref of
         Facts.Fact s => cartouche (simplify_spaces (YXML.content_of s)) ^ bracket
       | Facts.Named (("", _), _) => "[" ^ bracket ^ "]"
       | Facts.Named ((name, _), NONE) => make_name keywords (length ths > 1) (j + 1) name ^ bracket
       | Facts.Named ((name, _), SOME intervals) =>
         make_name keywords true
           (nth (maps (explode_interval (length ths)) intervals) j) name ^ bracket)
 
     fun add_nth th (j, rest) =
       let val name = nth_name j in
         (j + 1, ((name, stature_of_thm false [] chained css name th), th) :: rest)
       end
   in
     (0, []) |> fold add_nth ths |> snd
   end
 
 (* Reject theorems with names like "List.filter.filter_list_def" or "Accessible_Part.acc.defs", as
    these are definitions arising from packages. *)
 fun is_package_def s =
   exists (fn suf => String.isSuffix suf s)
     ["_case_def", "_rec_def", "_size_def", "_size_overloaded_def"]
   andalso
   let val ss = Long_Name.explode s in
     length ss > 2 andalso not (hd ss = "local")
   end
 
 (* FIXME: put other record thms here, or declare as "no_atp" *)
 val multi_base_blacklist =
   ["defs", "select_defs", "update_defs", "split", "splits", "split_asm", "ext_cases", "eq.simps",
    "eq.refl", "nchotomy", "case_cong", "case_cong_weak", "nat_of_char_simps", "nibble.simps",
    "nibble.distinct"]
   |> map (prefix Long_Name.separator)
 
 (* The maximum apply depth of any "metis" call in "Metis_Examples" (back in 2007) was 11. *)
 val max_apply_depth = 18
 
 fun apply_depth (f $ t) = Int.max (apply_depth f, apply_depth t + 1)
   | apply_depth (Abs (_, _, t)) = apply_depth t
   | apply_depth _ = 0
 
 fun is_too_complex t = apply_depth t > max_apply_depth
 
 (* FIXME: Ad hoc list *)
 val technical_prefixes =
   ["ATP", "Code_Evaluation", "Datatype", "Enum", "Lazy_Sequence", "Limited_Sequence", "Meson",
    "Metis", "Nitpick", "Quickcheck_Random", "Quickcheck_Exhaustive", "Quickcheck_Narrowing",
    "Random_Sequence", "Sledgehammer", "SMT"]
   |> map (suffix Long_Name.separator)
 
 fun is_technical_const s = exists (fn pref => String.isPrefix pref s) technical_prefixes
 
 (* FIXME: make more reliable *)
 val sep_class_sep = Long_Name.separator ^ "class" ^ Long_Name.separator
 
 fun is_low_level_class_const s =
   s = \<^const_name>\<open>equal_class.equal\<close> orelse String.isSubstring sep_class_sep s
 
 val sep_that = Long_Name.separator ^ Auto_Bind.thatN
 val skolem_thesis = Name.skolem Auto_Bind.thesisN
 
 fun is_that_fact th =
   exists_subterm (fn Free (s, _) => s = skolem_thesis | _ => false) (Thm.prop_of th)
   andalso String.isSuffix sep_that (Thm.get_name_hint th)
 
 datatype interest = Deal_Breaker | Interesting | Boring
 
 fun combine_interests Deal_Breaker _ = Deal_Breaker
   | combine_interests _ Deal_Breaker = Deal_Breaker
   | combine_interests Interesting _ = Interesting
   | combine_interests _ Interesting = Interesting
   | combine_interests Boring Boring = Boring
 
 val type_has_top_sort =
   exists_subtype (fn TFree (_, []) => true | TVar (_, []) => true | _ => false)
 
 fun is_likely_tautology_too_meta_or_too_technical th =
   let
     fun is_interesting_subterm (Const (s, _)) =
         not (member (op =) atp_widely_irrelevant_consts s)
       | is_interesting_subterm (Free _) = true
       | is_interesting_subterm _ = false
 
     fun interest_of_bool t =
       if exists_Const ((is_technical_const o fst) orf (is_low_level_class_const o fst) orf
           type_has_top_sort o snd) t then
         Deal_Breaker
       else if exists_type (exists_subtype (curry (op =) \<^typ>\<open>prop\<close>)) t orelse
           not (exists_subterm is_interesting_subterm t) then
         Boring
       else
         Interesting
 
     fun interest_of_prop _ \<^Const_>\<open>Trueprop for t\<close> = interest_of_bool t
       | interest_of_prop Ts \<^Const_>\<open>Pure.imp for t u\<close> =
         combine_interests (interest_of_prop Ts t) (interest_of_prop Ts u)
       | interest_of_prop Ts (Const (\<^const_name>\<open>Pure.all\<close>, _) $ Abs (_, T, t)) =
         if type_has_top_sort T then Deal_Breaker else interest_of_prop (T :: Ts) t
       | interest_of_prop Ts ((t as Const (\<^const_name>\<open>Pure.all\<close>, _)) $ u) =
         interest_of_prop Ts (t $ eta_expand Ts u 1)
       | interest_of_prop _ (Const (\<^const_name>\<open>Pure.eq\<close>, _) $ t $ u) =
         combine_interests (interest_of_bool t) (interest_of_bool u)
       | interest_of_prop _ _ = Deal_Breaker
 
     val t = Thm.prop_of th
   in
     (interest_of_prop [] t <> Interesting andalso not (Thm.eq_thm_prop (@{thm ext}, th))) orelse
     is_that_fact th
   end
 
 val is_blacklisted_or_something =
   let val blist = multi_base_blacklist in
     fn name => is_package_def name orelse exists (fn s => String.isSuffix s name) blist
   end
 
 (* This is a terrible hack. Free variables are sometimes coded as "M__" when
    they are displayed as "M" and we want to avoid clashes with these. But
    sometimes it's even worse: "Ma__" encodes "M". So we simply reserve all
    prefixes of all free variables. In the worse case scenario, where the fact
    won't be resolved correctly, the user can fix it manually, e.g., by giving a
    name to the offending fact. *)
 fun all_prefixes_of s = map (fn i => String.extract (s, 0, SOME i)) (1 upto size s - 1)
 
 fun close_form t =
   (t, [] |> Term.add_free_names t |> maps all_prefixes_of)
   |> fold (fn ((s, i), T) => fn (t', taken) =>
       let val s' = singleton (Name.variant_list taken) s in
         ((if fastype_of t' = HOLogic.boolT then HOLogic.all_const
           else Logic.all_const) T
          $ Abs (s', T, abstract_over (Var ((s, i), T), t')),
          s' :: taken)
       end)
     (Term.add_vars t [] |> sort_by (fst o fst))
   |> fst
 
 fun cartouche_term ctxt = close_form #> hackish_string_of_term ctxt #> cartouche
 fun cartouche_thm ctxt = cartouche_term ctxt o Thm.prop_of
 
 (* TODO: rewrite to use nets and/or to reuse existing data structures *)
 fun clasimpset_rule_table_of ctxt =
   let val simps = ctxt |> simpset_of |> dest_ss |> #simps in
     if length simps >= max_simps_for_clasimpset then
       Termtab.empty
     else
       let
         fun add stature th = Termtab.update (normalize_vars (Thm.prop_of th), stature)
 
         val {safeIs, (* safeEs, *) unsafeIs, (* unsafeEs, *) ...} =
           ctxt |> claset_of |> Classical.rep_cs
         val intros = map #1 (Item_Net.content safeIs @ Item_Net.content unsafeIs)
 (* Add once it is used:
         val elims = Item_Net.content safeEs @ Item_Net.content unsafeEs
           |> map Classical.classical_rule
 *)
         val specs = Spec_Rules.get ctxt
         val (rec_defs, nonrec_defs) = specs
           |> filter (Spec_Rules.is_equational o #rough_classification)
           |> maps #rules
           |> List.partition (is_rec_def o Thm.prop_of)
         val spec_intros = specs
           |> filter (Spec_Rules.is_relational o #rough_classification)
           |> maps #rules
       in
         Termtab.empty
         |> fold (add Simp o snd) simps
         |> fold (add Rec_Def) rec_defs
         |> fold (add Non_Rec_Def) nonrec_defs
 (* Add once it is used:
         |> fold (add Elim) elims
 *)
         |> fold (add Intro) intros
         |> fold (add Inductive) spec_intros
       end
   end
 
 fun normalize_eq (\<^Const_>\<open>Trueprop\<close> $ (t as (t0 as Const (\<^const_name>\<open>HOL.eq\<close>, _)) $ t1 $ t2)) =
     if is_less_equal (Term_Ord.fast_term_ord (t1, t2)) then t else t0 $ t2 $ t1
   | normalize_eq (\<^Const_>\<open>Trueprop\<close> $ (t as \<^Const_>\<open>Not\<close>
       $ ((t0 as Const (\<^const_name>\<open>HOL.eq\<close>, _)) $ t1 $ t2))) =
     if is_less_equal (Term_Ord.fast_term_ord (t1, t2)) then t else HOLogic.mk_not (t0 $ t2 $ t1)
   | normalize_eq (Const (\<^const_name>\<open>Pure.eq\<close>, Type (_, [T, _])) $ t1 $ t2) =
     (if is_less_equal (Term_Ord.fast_term_ord (t1, t2)) then (t1, t2) else (t2, t1))
     |> (fn (t1, t2) => HOLogic.eq_const T $ t1 $ t2)
   | normalize_eq t = t
 
 fun if_thm_before th th' =
   if Context.subthy_id (apply2 Thm.theory_id (th, th')) then th else th'
 
 (* Hack: Conflate the facts about a class as seen from the outside with the corresponding low-level
    facts, so that MaSh can learn from the low-level proofs. *)
 fun un_class_ify s =
   (case first_field "_class" s of
     SOME (pref, suf) => [s, pref ^ suf]
   | NONE => [s])
 
 fun build_name_tables name_of facts =
   let
     fun cons_thm (_, th) = Termtab.cons_list (normalize_vars (normalize_eq (Thm.prop_of th)), th)
     fun add_plain canon alias =
       Symtab.update (Thm.get_name_hint alias, name_of (if_thm_before canon alias))
     fun add_plains (_, aliases as canon :: _) = fold (add_plain canon) aliases
     fun add_inclass (name, target) = fold (fn s => Symtab.update (s, target)) (un_class_ify name)
     val prop_tab = fold cons_thm facts Termtab.empty
     val plain_name_tab = Termtab.fold add_plains prop_tab Symtab.empty
     val inclass_name_tab = Symtab.fold add_inclass plain_name_tab Symtab.empty
   in
     (plain_name_tab, inclass_name_tab)
   end
 
 fun fact_distinct eq facts =
   fold (fn (i, fact as (_, th)) =>
       Net.insert_term_safe (eq o apply2 (normalize_eq o Thm.prop_of o snd o snd))
         (normalize_eq (Thm.prop_of th), (i, fact)))
     (tag_list 0 facts) Net.empty
   |> Net.entries
   |> sort (int_ord o apply2 fst)
   |> map snd
 
 fun struct_induct_rule_on th =
   (case Logic.strip_horn (Thm.prop_of th) of
     (prems, \<^Const_>\<open>Trueprop\<close> $ ((p as Var ((p_name, 0), _)) $ (a as Var (_, ind_T)))) =>
     if not (is_TVar ind_T) andalso length prems > 1 andalso
        exists (exists_subterm (curry (op aconv) p)) prems andalso
        not (exists (exists_subterm (curry (op aconv) a)) prems) then
       SOME (p_name, ind_T)
     else
       NONE
   | _ => NONE)
 
 val instantiate_induct_timeout = seconds 0.01
 
 fun instantiate_induct_rule ctxt concl_prop p_name ((name, stature), th) ind_x =
   let
     fun varify_noninducts (t as Free (s, T)) =
-        if (s, T) = ind_x orelse can dest_funT T then t else Var ((s, 0), T)
+        if (s, T) = ind_x then t else Var ((s, 0), T)
       | varify_noninducts t = t
 
     val p_inst = concl_prop
       |> map_aterms varify_noninducts
       |> close_form
       |> lambda (Free ind_x)
       |> hackish_string_of_term ctxt
   in
     ((fn () => name () ^ "[where " ^ p_name ^ " = " ^ quote p_inst ^ "]", stature),
      th |> Rule_Insts.read_instantiate ctxt [(((p_name, 0), Position.none), p_inst)] [])
   end
 
 fun type_match thy (T1, T2) =
   (Sign.typ_match thy (T2, T1) Vartab.empty; true)
   handle Type.TYPE_MATCH => false
 
 fun instantiate_if_induct_rule ctxt stmt stmt_xs (ax as (_, th)) =
   (case struct_induct_rule_on th of
     SOME (p_name, ind_T) =>
     let val thy = Proof_Context.theory_of ctxt in
       stmt_xs
       |> filter (fn (_, T) => type_match thy (T, ind_T))
       |> map_filter (try (Timeout.apply instantiate_induct_timeout
         (instantiate_induct_rule ctxt stmt p_name ax)))
     end
   | NONE => [ax])
 
 fun external_frees t =
   [] |> Term.add_frees t |> filter_out (Name.is_internal o fst)
 
 fun instantiate_inducts ctxt hyp_ts concl_t =
   let
     val ind_stmt =
       (hyp_ts |> filter_out (null o external_frees), concl_t)
       |> Logic.list_implies |> Object_Logic.atomize_term ctxt
     val ind_stmt_xs = external_frees ind_stmt
   in
     maps (instantiate_if_induct_rule ctxt ind_stmt ind_stmt_xs)
   end
 
 fun fact_of_lazy_fact ((name, stature), th) = ((name (), stature), th)
 
 fun fact_count facts = Facts.fold_static (K (Integer.add 1)) facts 0
 
 fun is_useful_unnamed_local_fact ctxt =
   let
     val thy = Proof_Context.theory_of ctxt
     val global_facts = Global_Theory.facts_of thy
     val local_facts = Proof_Context.facts_of ctxt
     val named_locals = Facts.dest_static true [global_facts] local_facts
       |> maps (map (normalize_eq o Thm.prop_of) o snd)
   in
     fn th =>
       not (Thm.has_name_hint th) andalso
       not (member (op aconv) named_locals (normalize_eq (Thm.prop_of th)))
   end
 
 fun all_facts ctxt generous keywords add_ths chained css =
   let
     val thy = Proof_Context.theory_of ctxt
     val transfer = Global_Theory.transfer_theories thy
     val global_facts = Global_Theory.facts_of thy
     val is_too_complex =
       if generous orelse fact_count global_facts >= max_facts_for_complex_check then K false
       else is_too_complex
     val local_facts = Proof_Context.facts_of ctxt
     val assms = Assumption.all_assms_of ctxt
     val named_locals = Facts.dest_static true [global_facts] local_facts
     val unnamed_locals =
       Facts.props local_facts
       |> map #1
       |> filter (is_useful_unnamed_local_fact ctxt)
       |> map (pair "" o single)
 
     val full_space = Name_Space.merge (Facts.space_of global_facts, Facts.space_of local_facts)
 
     fun add_facts global foldx facts =
       foldx (fn (name0, ths) => fn accum =>
         if name0 <> "" andalso
            (Long_Name.is_hidden (Facts.intern facts name0) orelse
             ((Facts.is_concealed facts name0 orelse
               (not generous andalso is_blacklisted_or_something name0)) andalso
              forall (not o member Thm.eq_thm_prop add_ths) ths)) then
           accum
         else
           let
             val n = length ths
             val collection = n > 1
             val dotted_name = length (Long_Name.explode name0) > 2 (* ignore theory name *)
 
             fun check_thms a =
               (case try (Proof_Context.get_thms ctxt) a of
                 NONE => false
               | SOME ths' => eq_list Thm.eq_thm_prop (ths, ths'))
           in
             snd (fold_rev (fn th0 => fn (j, accum) =>
               let val th = transfer th0 in
                 (j - 1,
                  if not (member Thm.eq_thm_prop add_ths th) andalso
                     (is_likely_tautology_too_meta_or_too_technical th orelse
                      is_too_complex (Thm.prop_of th)) then
                    accum
                  else
                    let
                      fun get_name () =
                        if name0 = "" orelse name0 = local_thisN then
                          cartouche_thm ctxt th
                        else
                          let val short_name = Facts.extern ctxt facts name0 in
                            if check_thms short_name then
                              short_name
                            else
                              let val long_name = Name_Space.extern ctxt full_space name0 in
                                if check_thms long_name then
                                  long_name
                                else
                                  name0
                              end
                          end
                          |> make_name keywords collection j
                      val stature = stature_of_thm global assms chained css name0 th
                      val new = ((get_name, stature), th)
                    in
                      (if collection then apsnd o apsnd
                       else if dotted_name then apsnd o apfst
                       else apfst) (cons new) accum
                    end)
               end) ths (n, accum))
           end)
   in
     (* Names like "xxx" are preferred to "xxx.yyy", which are preferred to "xxx(666)" and the like.
        "Preferred" means "put to the front of the list". *)
     ([], ([], []))
     |> add_facts false fold local_facts (unnamed_locals @ named_locals)
     |> add_facts true Facts.fold_static global_facts global_facts
     ||> op @ |> op @
   end
 
 fun nearly_all_facts ctxt inst_inducts {add, del, only} keywords css chained hyp_ts
     concl_t =
   if only andalso null add then
     []
   else
     let
       val chained = chained |> maps (fn th => insert Thm.eq_thm_prop (zero_var_indexes th) [th])
     in
       (if only then
          maps (map (fn ((name, stature), th) => ((K name, stature), th))
            o fact_of_ref ctxt keywords chained css) add
        else
          let
            val (add, del) = apply2 (Attrib.eval_thms ctxt) (add, del)
            val facts =
              all_facts ctxt false keywords add chained css
              |> filter_out ((member Thm.eq_thm_prop del orf
                (Named_Theorems.member ctxt \<^named_theorems>\<open>no_atp\<close> andf
                  not o member Thm.eq_thm_prop add)) o snd)
          in
            facts
          end)
       |> inst_inducts ? instantiate_inducts ctxt hyp_ts concl_t
     end
 
 fun nearly_all_facts_of_context ctxt inst_inducts fact_override =
   let
     val keywords = Thy_Header.get_keywords' ctxt
     val css = clasimpset_rule_table_of ctxt
   in
     nearly_all_facts ctxt inst_inducts fact_override keywords css
   end
 
 fun drop_duplicate_facts facts =
   let val num_facts = length facts in
     facts |> num_facts <= max_facts_for_duplicates ? fact_distinct (op aconv)
   end
 
 end;