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(********************************************************************)
(*                                                                  *)
(*  The Why3 Verification Platform   /   The Why3 Development Team  *)
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(*  Copyright 2010-2018   --   Inria - CNRS - Paris-Sud University  *)
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(*                                                                  *)
(*  This software is distributed under the terms of the GNU Lesser  *)
(*  General Public License version 2.1, with the special exception  *)
(*  on linking described in file LICENSE.                           *)
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(*                                                                  *)
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(********************************************************************)
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open Wstdlib
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open Ident
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open Ptree
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open Ty
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open Term
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open Decl
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open Theory
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open Dterm
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open Ity
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open Expr
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open Pdecl
open Pmodule
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(** debug flags *)
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let debug_parse_only = Debug.register_flag "parse_only"
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  ~desc:"Stop@ after@ parsing."
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let debug_type_only  = Debug.register_flag "type_only"
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  ~desc:"Stop@ after@ type-checking."
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let debug_useless_at = Debug.register_flag "ignore_useless_at"
  ~desc:"Remove@ warning@ for@ useless@ at/old."

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(** symbol lookup *)
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let rec qloc = function
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  | Qdot (p, id) -> Loc.join (qloc p) id.id_loc
  | Qident id    -> id.id_loc

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let qloc_last = function
  | Qdot (_, id) | Qident id -> id.id_loc

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let rec print_qualid fmt = function
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  | Qdot (p, id) ->
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      Format.fprintf fmt "%a.%a" print_qualid p Ident.print_decoded id.id_str
  | Qident id -> Ident.print_decoded fmt id.id_str
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let string_list_of_qualid q =
  let rec sloq acc = function
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    | Qdot (p, id) -> sloq (id.id_str :: acc) p
    | Qident id -> id.id_str :: acc in
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  sloq [] q
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exception UnboundSymbol of qualid
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let find_qualid get_id find ns q =
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  let sl = string_list_of_qualid q in
  let r = try find ns sl with Not_found ->
    Loc.error ~loc:(qloc q) (UnboundSymbol q) in
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  if Debug.test_flag Glob.flag then Glob.use ~kind:"" (qloc_last q) (get_id r);
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  r
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let find_prop_ns     ns q = find_qualid (fun pr -> pr.pr_name) ns_find_pr ns q
let find_tysymbol_ns ns q = find_qualid (fun ts -> ts.ts_name) ns_find_ts ns q
let find_lsymbol_ns  ns q = find_qualid (fun ls -> ls.ls_name) ns_find_ls ns q
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let find_fsymbol_ns ns q =
  let ls = find_lsymbol_ns ns q in
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  if ls.ls_value <> None then ls else
    Loc.error ~loc:(qloc q) (FunctionSymbolExpected ls)
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let find_psymbol_ns ns q =
  let ls = find_lsymbol_ns ns q in
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  if ls.ls_value = None then ls else
    Loc.error ~loc:(qloc q) (PredicateSymbolExpected ls)
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let find_tysymbol tuc q = find_tysymbol_ns (Theory.get_namespace tuc) q
let find_lsymbol  tuc q = find_lsymbol_ns  (Theory.get_namespace tuc) q
let find_fsymbol  tuc q = find_fsymbol_ns  (Theory.get_namespace tuc) q
let find_psymbol  tuc q = find_psymbol_ns  (Theory.get_namespace tuc) q
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let find_prop     tuc q = find_prop_ns     (Theory.get_namespace tuc) q

let find_prop_of_kind k tuc q =
  let pr = find_prop tuc q in
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  match (Mid.find pr.pr_name tuc.uc_known).d_node with
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  | Dind _ when k = Paxiom -> pr
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  | Dprop (l,_,_) when l = k -> pr
  | _ -> Loc.errorm ~loc:(qloc q) "proposition %a is not %s"
      print_qualid q (match k with
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        | Plemma -> "a lemma" | Paxiom -> "an axiom" | Pgoal -> "a goal")
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let find_itysymbol_ns ns q =
  find_qualid (fun s -> s.its_ts.ts_name) Pmodule.ns_find_its ns q

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let find_xsymbol_ns ns q =
  find_qualid (fun s -> s.xs_name) Pmodule.ns_find_xs ns q

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let find_prog_symbol_ns ns p =
  let get_id_ps = function
    | PV pv -> pv.pv_vs.vs_name
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    | RS rs -> rs.rs_name
      (* FIXME: this is incorrect, but we cannot
        know the correct symbol at this stage *)
    | OO ss -> (Srs.choose ss).rs_name in
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  find_qualid get_id_ps ns_find_prog_symbol ns p

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(** Parsing types *)

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let rec ty_of_pty ns = function
  | PTtyvar {id_str = x} ->
      ty_var (tv_of_string x)
  | PTtyapp (q, tyl) ->
      let ts = find_tysymbol_ns ns q in
      let tyl = List.map (ty_of_pty ns) tyl in
      Loc.try2 ~loc:(qloc q) ty_app ts tyl
  | PTtuple tyl ->
      let s = its_tuple (List.length tyl) in
      ty_app s.its_ts (List.map (ty_of_pty ns) tyl)
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  | PTref tyl ->
      ty_app ts_ref (List.map (ty_of_pty ns) tyl)
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  | PTarrow (ty1, ty2) ->
      ty_func (ty_of_pty ns ty1) (ty_of_pty ns ty2)
  | PTscope (q, ty) ->
      let ns = import_namespace ns (string_list_of_qualid q) in
      ty_of_pty ns ty
  | PTpure ty | PTparen ty ->
      ty_of_pty ns ty
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let dty_of_pty ns pty =
  Dterm.dty_of_ty (ty_of_pty ns pty)
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let dty_of_opt ns = function
  | Some pty -> dty_of_pty ns pty
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  | None -> Dterm.dty_fresh ()

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(** typing using destructive type variables
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    parsed trees        intermediate trees       typed trees
      (Ptree)                (Dterm)               (Term)
   -----------------------------------------------------------
     ppure_type  ---dty--->   dty       ---ty--->    ty
      lexpr      --dterm-->   dterm     --term-->    term
*)
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(** Typing patterns, terms, and formulas *)

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let create_user_prog_id {id_str = n; id_ats = attrs; id_loc = loc} =
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  let get_attrs (attrs, loc) = function
    | ATstr attr -> Sattr.add attr attrs, loc | ATpos loc -> attrs, loc in
  let attrs, loc = List.fold_left get_attrs (Sattr.empty, loc) attrs in
  id_user ~attrs n loc
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let create_user_id id =
  let id = create_user_prog_id id in
  if Sattr.mem Pmodule.ref_attr id.pre_attrs then Loc.errorm ?loc:id.pre_loc
    "reference markers are only admitted over program variables";
  id

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let parse_record ~loc ns km get_val fl =
  let fl = List.map (fun (q,e) -> find_lsymbol_ns ns q, e) fl in
  let cs,pjl,flm = Loc.try2 ~loc parse_record km fl in
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  let get_val pj = get_val cs pj (Mls.find_opt pj flm) in
  cs, List.map get_val pjl

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let rec dpattern ns km { pat_desc = desc; pat_loc = loc } =
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  match desc with
    | Ptree.Pparen p -> dpattern ns km p
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    | Ptree.Pscope (q,p) ->
        let ns = import_namespace ns (string_list_of_qualid q) in
        dpattern ns km p
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    | _ -> (* creative indentation ahead *)
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  Dterm.dpattern ~loc (match desc with
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    | Ptree.Pparen _
    | Ptree.Pscope _ -> assert false (* never *)
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    | Ptree.Pwild -> DPwild
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    | Ptree.Pvar x -> DPvar (create_user_id x)
    | Ptree.Papp (q,pl) ->
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        let pl = List.map (dpattern ns km) pl in
        DPapp (find_lsymbol_ns ns q, pl)
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    | Ptree.Ptuple pl ->
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        let pl = List.map (dpattern ns km) pl in
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        DPapp (fs_tuple (List.length pl), pl)
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    | Ptree.Prec fl ->
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        let get_val _ _ = function
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          | Some p -> dpattern ns km p
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          | None -> Dterm.dpattern DPwild in
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        let cs,fl = parse_record ~loc ns km get_val fl in
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        DPapp (cs,fl)
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    | Ptree.Pas (p,x,false) -> DPas (dpattern ns km p, create_user_id x)
    | Ptree.Por (p,q) -> DPor (dpattern ns km p, dpattern ns km q)
    | Ptree.Pcast (p,ty) -> DPcast (dpattern ns km p, dty_of_pty ns ty)
    | Ptree.Pghost _ | Ptree.Pas (_,_,true) ->
        Loc.errorm ~loc "ghost patterns are only allowed in programs")
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let quant_var ns (loc, id, gh, ty) =
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  if gh then Loc.errorm ~loc "ghost variables are only allowed in programs";
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  Opt.map create_user_id id, dty_of_opt ns ty, Some loc
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let loc_cutoff loc13 loc23 loc2 =
  let f,l,b,e = Loc.get loc13 in
  let _,_,_,w = Loc.get loc23 in
  let _,_,_,m = Loc.get loc2 in
  Loc.user_position f l b (e - (w - m))

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let is_reusable dt = match dt.dt_node with
  | DTvar _ | DTgvar _ | DTconst _ | DTtrue | DTfalse -> true
  | DTapp (_,[]) -> true
  | _ -> false

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let mk_var crcmap n dt =
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  let dty = match dt.dt_dty with
    | None -> dty_of_ty ty_bool
    | Some dty -> dty in
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  Dterm.dterm crcmap ?loc:dt.dt_loc (DTvar (n, dty))
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let mk_let crcmap ~loc n dt node =
  DTlet (dt, id_user n loc, Dterm.dterm crcmap ~loc node)
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let mk_closure crcmap loc ls =
  let mk dt = Dterm.dterm crcmap ~loc dt in
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  let mk_v i _ =
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    Some (id_user ("y" ^ string_of_int i) loc), dty_fresh (), None in
  let mk_t (id, dty, _) = mk (DTvar ((Opt.get id).pre_name, dty)) in
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  let vl = Lists.mapi mk_v ls.ls_args in
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  DTquant (DTlambda, vl, [], mk (DTapp (ls, List.map mk_t vl)))
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(* handle auto-dereference in logical terms *)

let vs_dref vs = Sattr.mem Pmodule.ref_attr vs.vs_name.id_attrs

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let to_deref = function
  | DTvar _ -> true (* needed for DEpure *)
  | DTgvar vs -> vs_dref vs
  | _ -> false

let rec underef ({dt_loc = loc} as dt) = match dt.dt_node with
  | DTuloc (dt,l) -> Dterm.dterm ?loc Coercion.empty (DTuloc (underef dt, l))
  | DTattr (dt,a) -> Dterm.dterm ?loc Coercion.empty (DTattr (underef dt, a))
  | DTcast (dt,_) -> underef dt (* already unified *)
  | DTapp (ls, [dt]) when ls_equal ls ls_ref_proj && to_deref dt.dt_node -> dt
  | _ -> raise Not_found

let undereference dt = try underef dt with Not_found ->
  Loc.errorm ?loc:dt.dt_loc "not a reference variable"

let to_underef ls el e =
  let rec down al el = match al, el with
    | (_::al), (_::el) -> down al el
    | a::_, [] when vs_dref a.pv_vs ->
        (try underef e with Not_found -> e)
    | _::_, [] -> e
    | _ -> assert false in
  match Expr.restore_rs ls with
  | rs -> down rs.rs_cty.cty_args el
  | exception Not_found -> e

let dt_app ls el =
  let rec apply al l el = match l, el with
    | ({ty_node = Tyapp (ts,_)}::l), (e::el)
      when ts_equal ts Pmodule.ts_ref ->
        (* ls may be a let-function with ref params *)
        apply (to_underef ls al e::al) l el
    | (_::l), (e::el) -> apply (e::al) l el
    | _ -> DTapp (ls, List.rev_append al el) in
  apply [] ls.ls_args el
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(* track the use of labels *)
let at_uses = Hstr.create 5

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let rec dterm ns km crcmap gvars at denv {term_desc = desc; term_loc = loc} =
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  let func_app e el =
    List.fold_left (fun e1 (loc, e2) ->
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      DTfapp (Dterm.dterm crcmap ~loc e1, e2)) e el
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  in
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  let rec apply_ls loc ls al l el = match l, el with
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    | ({ty_node = Tyapp (ts,_)}::l), ((loc_e,e)::el)
      when ts_equal ts Pmodule.ts_ref ->
        (* ls may be a let-function with ref params *)
        apply_ls loc ls ((loc_e, to_underef ls al e)::al) l el
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    | (_::l), (e::el) -> apply_ls loc ls (e::al) l el
    | [], _ -> func_app (DTapp (ls, List.rev_map snd al)) el
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    | _, [] -> func_app (mk_closure crcmap loc ls) (List.rev_append al el)
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  in
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  let qualid_app q el = match gvars at q with
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    | Some v ->
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        let attrs = match at with
          | Some l -> (* check for impact *)
              let u = Opt.get (gvars None q) in
              if pv_equal v u then Sattr.empty else begin
                let attr = create_attribute ("at:" ^ l) in
                Hstr.replace at_uses l true;
                Sattr.singleton attr
              end
          | None -> Sattr.empty
        in
        let e = DTgvar v.pv_vs in
        let e = if Sattr.is_empty attrs then e else
          DTattr (Dterm.dterm crcmap ~loc e, attrs) in
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        if vs_dref v.pv_vs then
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          let e = Dterm.dterm crcmap ~loc e in
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          let loc = qloc q and ls = Pmodule.ls_ref_proj in
          apply_ls loc ls [] ls.ls_args ((loc, e)::el)
        else
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          func_app e el
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    | None ->
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        let ls = find_lsymbol_ns ns q in
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        apply_ls (qloc q) ls [] ls.ls_args el
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  in
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  let qualid_app q el = match q with
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    | Qident {id_str = n} ->
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        (match denv_get_opt denv n with
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        | Some d -> func_app d el
        | None -> qualid_app q el)
    | _ -> qualid_app q el
  in
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  let rec unfold_app e1 e2 el = match e1.term_desc with
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    | Ptree.Tapply (e11,e12) ->
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        let e12 = dterm ns km crcmap gvars at denv e12 in
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        unfold_app e11 e12 ((e1.term_loc, e2)::el)
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    | Ptree.Tident q ->
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        qualid_app q ((e1.term_loc, e2)::el)
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    | _ ->
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        func_app (DTfapp (dterm ns km crcmap gvars at denv e1, e2)) el
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  in
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  Dterm.dterm crcmap ~loc (match desc with
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  | Ptree.Tident q ->
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      qualid_app q []
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  | Ptree.Tidapp (q, tl) ->
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      let tl = List.map (dterm ns km crcmap gvars at denv) tl in
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      dt_app (find_lsymbol_ns ns q) tl
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  | Ptree.Tapply (e1, e2) ->
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      unfold_app e1 (dterm ns km crcmap gvars at denv e2) []
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  | Ptree.Ttuple tl ->
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      let tl = List.map (dterm ns km crcmap gvars at denv) tl in
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      DTapp (fs_tuple (List.length tl), tl)
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  | Ptree.Tinfix (e1, op1, e23)
  | Ptree.Tinnfix (e1, op1, e23) ->
      let apply loc de1 op de2 =
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        if op.id_str = Ident.op_neq then
          let op = { op with id_str = Ident.op_equ } in
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          let ls = find_lsymbol_ns ns (Qident op) in
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          DTnot (Dterm.dterm crcmap ~loc (dt_app ls [de1;de2]))
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        else
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          dt_app (find_lsymbol_ns ns (Qident op)) [de1;de2] in
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      let rec chain loc de1 op1 = function
        | { term_desc = Ptree.Tinfix (e2, op2, e3); term_loc = loc23 } ->
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            let de2 = dterm ns km crcmap gvars at denv e2 in
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            let loc12 = loc_cutoff loc loc23 e2.term_loc in
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            let de12 = Dterm.dterm crcmap ~loc:loc12 (apply loc12 de1 op1 de2) in
            let de23 = Dterm.dterm crcmap ~loc:loc23 (chain loc23 de2 op2 e3) in
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            DTbinop (DTand, de12, de23)
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        | e23 ->
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            apply loc de1 op1 (dterm ns km crcmap gvars at denv e23) in
      chain loc (dterm ns km crcmap gvars at denv e1) op1 e23
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  | Ptree.Tconst (Number.ConstInt _ as c) ->
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      DTconst (c, dty_int)
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  | Ptree.Tconst (Number.ConstReal _ as c) ->
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      DTconst (c, dty_real)
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  | Ptree.Tlet (x, e1, e2) ->
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      let id = create_user_id x in
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      let e1 = dterm ns km crcmap gvars at denv e1 in
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      let denv = denv_add_let denv e1 id in
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      let e2 = dterm ns km crcmap gvars at denv e2 in
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      DTlet (e1, id, e2)
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  | Ptree.Tcase (e1, bl) ->
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      let e1 = dterm ns km crcmap gvars at denv e1 in
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      let branch (p, e) =
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        let p = dpattern ns km p in
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        let denv = denv_add_term_pat denv p e1 in
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        p, dterm ns km crcmap gvars at denv e in
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      DTcase (e1, List.map branch bl)
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  | Ptree.Tif (e1, e2, e3) ->
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      let e1 = dterm ns km crcmap gvars at denv e1 in
      let e2 = dterm ns km crcmap gvars at denv e2 in
      let e3 = dterm ns km crcmap gvars at denv e3 in
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      DTif (e1, e2, e3)
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  | Ptree.Ttrue ->
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      DTtrue
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  | Ptree.Tfalse ->
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      DTfalse
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  | Ptree.Tnot e1 ->
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      DTnot (dterm ns km crcmap gvars at denv e1)
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  | Ptree.Tbinop (e1, Dterm.DTiff, e23)
  | Ptree.Tbinnop (e1, Dterm.DTiff, e23) ->
      let rec chain loc de1 = function
        | { term_desc = Ptree.Tbinop (e2, DTiff, e3); term_loc = loc23 } ->
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            let de2 = dterm ns km crcmap gvars at denv e2 in
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            let loc12 = loc_cutoff loc loc23 e2.term_loc in
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            let de12 = Dterm.dterm crcmap ~loc:loc12 (DTbinop (DTiff, de1, de2)) in
            let de23 = Dterm.dterm crcmap ~loc:loc23 (chain loc23 de2 e3) in
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            DTbinop (DTand, de12, de23)
        | { term_desc = Ptree.Tbinop (_, DTimplies, _); term_loc = loc23 } ->
            Loc.errorm ~loc:loc23 "An unparenthesized implication cannot be \
              placed at the right hand side of an equivalence"
        | e23 ->
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            DTbinop (DTiff, de1, (dterm ns km crcmap gvars at denv e23)) in
      chain loc (dterm ns km crcmap gvars at denv e1) e23
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  | Ptree.Tbinop (e1, op, e2)
  | Ptree.Tbinnop (e1, op, e2) ->
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      let e1 = dterm ns km crcmap gvars at denv e1 in
      let e2 = dterm ns km crcmap gvars at denv e2 in
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      DTbinop (op, e1, e2)
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  | Ptree.Tquant (q, uqu, trl, e1) ->
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      let qvl = List.map (quant_var ns) uqu in
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      let denv = denv_add_quant denv qvl in
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      let dterm e = dterm ns km crcmap gvars at denv e in
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      let trl = List.map (List.map dterm) trl in
      let e1 = dterm e1 in
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      DTquant (q, qvl, trl, e1)
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  | Ptree.Trecord fl ->
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      let get_val _cs pj = function
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        | Some e -> dterm ns km crcmap gvars at denv e
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        | None -> Loc.error ~loc (RecordFieldMissing pj) in
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      let cs, fl = parse_record ~loc ns km get_val fl in
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      DTapp (cs, fl)
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  | Ptree.Tupdate (e1, fl) ->
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      let e1 = dterm ns km crcmap gvars at denv e1 in
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      let re = is_reusable e1 in
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      let v = if re then e1 else mk_var crcmap "q " e1 in
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      let get_val _ pj = function
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        | Some e -> dterm ns km crcmap gvars at denv e
        | None -> Dterm.dterm crcmap ~loc (DTapp (pj,[v])) in
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      let cs, fl = parse_record ~loc ns km get_val fl in
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      let d = DTapp (cs, fl) in
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      if re then d else mk_let crcmap ~loc "q " e1 d
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  | Ptree.Tat (e1, ({id_str = l; id_loc = loc} as id)) ->
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      Hstr.add at_uses l false;
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      let id = { id with id_str = "" } in
      (* check if the label has actually been defined *)
      ignore (Loc.try2 ~loc gvars (Some l) (Qident id));
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      let e1 = dterm ns km crcmap gvars (Some l) denv e1 in
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      if not (Hstr.find at_uses l) && Debug.test_noflag debug_useless_at then
        Warning.emit ~loc "this `at'/`old' operator is never used";
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      Hstr.remove at_uses l;
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      DTattr (e1, Sattr.empty)
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M.()  
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  | Ptree.Tscope (q, e1) ->
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      let ns = import_namespace ns (string_list_of_qualid q) in
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      DTattr (dterm ns km crcmap gvars at denv e1, Sattr.empty)
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  | Ptree.Tasref q ->
      let e1 = { term_desc = Tident q; term_loc = loc } in
      let d1 = dterm ns km crcmap gvars at denv e1 in
      DTattr (undereference d1, Sattr.empty)
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  | Ptree.Tattr (ATpos uloc, e1) ->
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      DTuloc (dterm ns km crcmap gvars at denv e1, uloc)
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  | Ptree.Tattr (ATstr attr, e1) ->
      DTattr (dterm ns km crcmap gvars at denv e1, Sattr.singleton attr)
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  | Ptree.Tcast ({term_desc = Ptree.Tconst c}, pty) ->
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      DTconst (c, dty_of_pty ns pty)
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  | Ptree.Tcast (e1, pty) ->
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      let d1 = dterm ns km crcmap gvars at denv e1 in
      DTcast (d1, dty_of_pty ns pty))
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let no_gvars at q = match at with
  | Some _ -> Loc.errorm ~loc:(qloc q)
      "`at' and `old' can only be used in program annotations"
  | None -> None
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let type_term_in_namespace ns km crcmap t =
  let t = dterm ns km crcmap no_gvars None Dterm.denv_empty t in
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  Dterm.term ~strict:true ~keep_loc:true t

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let type_fmla_in_namespace ns km crcmap f =
  let f = dterm ns km crcmap no_gvars None Dterm.denv_empty f in
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  Dterm.fmla ~strict:true ~keep_loc:true f
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(** typing program expressions *)
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open Dexpr

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let ty_of_pty tuc = ty_of_pty (get_namespace tuc)
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let get_namespace muc = List.hd muc.Pmodule.muc_import
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let dterm muc =
  let uc = muc.muc_theory in
  dterm (Theory.get_namespace uc) uc.uc_known uc.uc_crcmap

let find_xsymbol     muc q = find_xsymbol_ns     (get_namespace muc) q
let find_itysymbol   muc q = find_itysymbol_ns   (get_namespace muc) q
let find_prog_symbol muc q = find_prog_symbol_ns (get_namespace muc) q

let find_special muc test nm q =
  match find_prog_symbol muc q with
  | RS s when test s -> s
  | OO ss ->
      begin match Srs.elements (Srs.filter test ss) with
      | [s] -> s
      | _::_ -> Loc.errorm ~loc:(qloc q)
                          "Ambiguous %s notation: %a" nm print_qualid q
      | [] -> Loc.errorm ~loc:(qloc q) "Not a %s: %a" nm print_qualid q
      end
  | _ ->      Loc.errorm ~loc:(qloc q) "Not a %s: %a" nm print_qualid q

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let rec ity_of_pty muc = function
  | PTtyvar {id_str = x} ->
      ity_var (tv_of_string x)
  | PTtyapp (q, tyl) ->
      let s = find_itysymbol muc q in
      let tyl = List.map (ity_of_pty muc) tyl in
      Loc.try3 ~loc:(qloc q) ity_app s tyl []
  | PTtuple tyl ->
      ity_tuple (List.map (ity_of_pty muc) tyl)
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  | PTref tyl ->
      ity_app its_ref (List.map (ity_of_pty muc) tyl) []
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  | PTarrow (ty1, ty2) ->
      ity_func (ity_of_pty muc ty1) (ity_of_pty muc ty2)
  | PTpure ty ->
      ity_purify (ity_of_pty muc ty)
  | PTscope (q, ty) ->
      let muc = open_scope muc "dummy" in
      let muc = import_scope muc (string_list_of_qualid q) in
      ity_of_pty muc ty
  | PTparen ty ->
      ity_of_pty muc ty
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let dity_of_pty muc pty =
  Dexpr.dity_of_ity (ity_of_pty muc pty)

let dity_of_opt muc = function
  | Some pty -> dity_of_pty muc pty
  | None -> Dexpr.dity_fresh ()

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(* records *)

let find_record_field muc q =
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  let test rs = rs.rs_field <> None in
  find_special muc test "record field" q
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let find_record_field2 muc (q,e) = find_record_field muc q, e

let parse_record muc fll =
  (* we assume that every rsymbol in fll was resolved
     using find_record_field, so they are all fields *)
  let ls_of_rs rs = match rs.rs_logic with
    | RLls ls -> ls | _ -> assert false in
  let rs = match fll with
    | (rs, _)::_ -> rs
    | [] -> raise EmptyRecord in
  let its = match rs.rs_cty.cty_args with
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    | [{pv_ity = {ity_node = (Ityreg {reg_its = s} | Ityapp (s,_,_))}}] -> s
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    | _ -> raise (BadRecordField (ls_of_rs rs)) in
  let itd = find_its_defn muc.muc_known its in
  let check v s = match s.rs_field with
    | Some u -> pv_equal v u
    | _ -> false in
  let cs = match itd.itd_constructors with
    | [cs] when Lists.equal check cs.rs_cty.cty_args itd.itd_fields -> cs
    | _ -> raise (BadRecordField (ls_of_rs rs)) in
  let pjs = Srs.of_list itd.itd_fields in
  let flm = List.fold_left (fun m (pj,v) -> if Srs.mem pj pjs then
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    Mrs.add_new (DuplicateRecordField (ls_of_rs pj)) pj v m
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    else raise (BadRecordField (ls_of_rs pj))) Mrs.empty fll in
  cs, itd.itd_fields, flm

let parse_record ~loc muc get_val fl =
  let fl = List.map (find_record_field2 muc) fl in
  let cs,pjl,flm = Loc.try2 ~loc parse_record muc fl in
  let get_val pj = get_val cs pj (Mrs.find_opt pj flm) in
  cs, List.map get_val pjl

(* patterns *)

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let find_constructor muc q =
  let test rs = match rs.rs_logic with
    | RLls {ls_constr = c} -> c > 0
    | _ -> false in
  find_special muc test "constructor" q

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let rec dpattern muc gh { pat_desc = desc; pat_loc = loc } =
  match desc with
    | Ptree.Pparen p -> dpattern muc gh p
    | Ptree.Pghost p -> dpattern muc true p
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    | Ptree.Pscope (q,p) ->
        let muc = open_scope muc "dummy" in
        let muc = import_scope muc (string_list_of_qualid q) in
        dpattern muc gh p
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    | _ -> (* creative indentation ahead *)
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  Dexpr.dpattern ~loc (match desc with
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    | Ptree.Pparen _ | Ptree.Pscope _
    | Ptree.Pghost _ -> assert false (* never *)
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    | Ptree.Pwild -> DPwild
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    | Ptree.Pvar x -> DPvar (create_user_prog_id x, gh)
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    | Ptree.Papp (q,pl) ->
        DPapp (find_constructor muc q, List.map (dpattern muc gh) pl)
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    | Ptree.Prec fl ->
        let get_val _ _ = function
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          | Some p -> dpattern muc gh p
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          | None -> Dexpr.dpattern DPwild in
        let cs,fl = parse_record ~loc muc get_val fl in
        DPapp (cs,fl)
    | Ptree.Ptuple pl ->
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        DPapp (rs_tuple (List.length pl), List.map (dpattern muc gh) pl)
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    | Ptree.Pcast (p,pty) ->
        DPcast (dpattern muc gh p, dity_of_pty muc pty)
    | Ptree.Pas (p,x,g) ->
        DPas (dpattern muc gh p, create_user_prog_id x, gh || g)
    | Ptree.Por (p,q) ->
        DPor (dpattern muc gh p, dpattern muc gh q))
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let dpattern muc pat = dpattern muc false pat
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(* specifications *)

let find_global_pv muc q = try match find_prog_symbol muc q with
  | PV v -> Some v | _ -> None with _ -> None

let find_local_pv muc lvm q = match q with
  | Qdot _ -> find_global_pv muc q
  | Qident id -> let ovs = Mstr.find_opt id.id_str lvm in
      if ovs = None then find_global_pv muc q else ovs

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let mk_gvars muc lvm old = fun at q ->
  match find_local_pv muc lvm q, at with
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  | Some v, Some l -> Some (old l v)
  | None, Some l ->
      begin match q with
      (* normally, we have no reason to call "old" without
         a pvsymbol, but we make an exception for an empty
         ident to check if the label is valid at Tat *)
      | Qident {id_str = ""} -> Opt.map (old l) None
      | _ -> None end
  | v, None -> v
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let type_term muc lvm old t =
  let gvars = mk_gvars muc lvm old in
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  let t = dterm muc gvars None Dterm.denv_empty t in
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  Dterm.term ~strict:true ~keep_loc:true t
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let type_fmla muc lvm old f =
  let gvars = mk_gvars muc lvm old in
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  let f = dterm muc gvars None Dterm.denv_empty f in
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  Dterm.fmla ~strict:true ~keep_loc:true f
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let dpre muc pl lvm old =
  let dpre f = type_fmla muc lvm old f in
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  List.map dpre pl

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let dpost muc ql lvm old ity =
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  let mk_case loc pfl =
    let v = create_pvsymbol (id_fresh "result") ity in
    let i = { id_str = "(null)"; id_loc = loc; id_ats = [] } in
    let t = { term_desc = Tident (Qident i); term_loc = loc } in
    let f = { term_desc = Ptree.Tcase (t, pfl); term_loc = loc } in
    let lvm = Mstr.add "(null)" v lvm in
    v, Loc.try3 ~loc type_fmla muc lvm old f in
  let dpost (loc,pfl) = match pfl with
    | [pat, f] ->
        let rec unfold p = match p.pat_desc with
          | Ptree.Pparen p | Ptree.Pscope (_,p) -> unfold p
          | Ptree.Pcast (p,pty) ->
              let ty = ty_of_ity (ity_of_pty muc pty) in
              Loc.try2 ~loc:p.pat_loc ty_equal_check (ty_of_ity ity) ty;
              unfold p
          | Ptree.Ptuple [] ->
              Loc.try2 ~loc:p.pat_loc ity_equal_check ity ity_unit;
              unfold { p with pat_desc = Ptree.Pwild }
          | Ptree.Pwild ->
              let v = create_pvsymbol (id_fresh "result") ity in
              v, Loc.try3 ~loc type_fmla muc lvm old f
          | Ptree.Pvar id ->
              let v = create_pvsymbol (create_user_id id) ity in
              let lvm = Mstr.add id.id_str v lvm in
              v, Loc.try3 ~loc type_fmla muc lvm old f
          | _ -> mk_case loc pfl in
        unfold pat
    | _ -> mk_case loc pfl in
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  List.map dpost ql

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let dxpost muc ql lvm xsm old =
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  let add_exn (q,pf) m =
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    let xs = match q with
      | Qident i ->
          begin try Mstr.find i.id_str xsm with
          | Not_found -> find_xsymbol muc q end
      | _ -> find_xsymbol muc q in
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    Mxs.change (fun l -> match pf, l with
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      | Some pf, Some l -> Some (pf :: l)
      | Some pf, None   -> Some (pf :: [])
      | None,    None   -> Some []
      | None,    Some _ -> l) xs m in
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  let mk_xpost loc xs pfl =
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    if pfl = [] then [] else
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    dpost muc [loc,pfl] lvm old xs.xs_ity in
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  let exn_map (loc,xpfl) =
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    let m = List.fold_right add_exn xpfl Mxs.empty in
    Mxs.mapi (fun xs pfl -> mk_xpost loc xs pfl) m in
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  let add_map ql m =
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    Mxs.union (fun _ l r -> Some (l @ r)) (exn_map ql) m in
  List.fold_right add_map ql Mxs.empty
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let dreads muc rl lvm =
  let dreads q = match find_local_pv muc lvm q with Some v -> v
    | None -> Loc.errorm ~loc:(qloc q) "Not a variable: %a" print_qualid q in
  List.map dreads rl

let dwrites muc wl lvm =
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  let old _ _ = Loc.errorm
    "`at' and `old' cannot be used in the `writes' clause" in
  let dwrites t = type_term muc lvm old t in
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  List.map dwrites wl

let find_variant_ls muc q = match find_lsymbol muc.muc_theory q with
  | { ls_args = [u;v]; ls_value = None } as ls when ty_equal u v -> ls
  | s -> Loc.errorm ~loc:(qloc q) "Not an order relation: %a" Pretty.print_ls s

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let dvariant muc varl lvm _xsm old =
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  let dvar t = type_term muc lvm old t in
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  let dvar (t,q) = dvar t, Opt.map (find_variant_ls muc) q in
  List.map dvar varl

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let dspec muc sp lvm xsm old ity = {
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  ds_pre     = dpre muc sp.sp_pre lvm old;
  ds_post    = dpost muc sp.sp_post lvm old ity;
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  ds_xpost   = dxpost muc sp.sp_xpost lvm xsm old;
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  ds_reads   = dreads muc sp.sp_reads lvm;
  ds_writes  = dwrites muc sp.sp_writes lvm;
  ds_checkrw = sp.sp_checkrw;
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  ds_diverge = sp.sp_diverge;
  ds_partial = sp.sp_partial; }
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let dspec_no_variant muc sp = match sp.sp_variant with
  | ({term_loc = loc},_)::_ ->
      Loc.errorm ~loc "unexpected 'variant' clause"
  | _ -> dspec muc sp

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let dassert muc f lvm _xsm old = type_fmla muc lvm old f
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let dinvariant muc f lvm _xsm old = dpre muc f lvm old
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(* abstract values *)

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let dparam muc (_,id,gh,pty) =
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  Opt.map create_user_prog_id id, gh, dity_of_pty muc pty
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let dbinder muc (_,id,gh,opt) =
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  Opt.map create_user_prog_id id, gh, dity_of_opt muc opt
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(* expressions *)

let is_reusable de = match de.de_node with
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  | DEvar _ | DEsym _ -> true | _ -> false
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let mk_var n { de_dvty = (argl, _ as dvty); de_loc = loc } =
  let dref = List.map Util.ffalse argl, false in
  Dexpr.dexpr ?loc (DEvar (n, dvty, dref))
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let mk_let ~loc n de node =
  let de1 = Dexpr.dexpr ~loc node in
  DElet ((id_user n loc, false, RKnone, de), de1)

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let update_any kind e = match e.expr_desc with
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  | Ptree.Eany (pl, _, pty, msk, sp) ->
      { e with expr_desc = Ptree.Eany (pl, kind, pty, msk, sp) }
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  | _ -> e

let local_kind = function
  | RKfunc | RKpred -> RKlocal
  | k -> k

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let undereference ({de_loc = loc} as de) =
  try Dexpr.undereference de with Not_found ->
    Loc.errorm ?loc "not a reference variable"

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let rec eff_dterm muc denv {term_desc = desc; term_loc = loc} =
  let expr_app loc e el =
    List.fold_left (fun e1 e2 ->
      DEapp (Dexpr.dexpr ~loc e1, e2)) e el
  in
  let qualid_app loc q el =
    let e = try DEsym (find_prog_symbol muc q) with
      | _ -> DEls_pure (find_lsymbol muc.muc_theory q, false) in
    expr_app loc e el
  in
  let qualid_app loc q el = match q with
    | Qident {id_str = n} ->
        (match denv_get_opt denv n with
        | Some d -> expr_app loc d el
        | None -> qualid_app loc q el)
    | _ -> qualid_app loc q el
  in
  Dexpr.dexpr ~loc (match desc with
  | Ptree.Tident q ->
      qualid_app loc q []
  | Ptree.Tidapp (q, [e1]) ->
      qualid_app loc q [eff_dterm muc denv e1]
  | Ptree.Tapply (e1, e2) ->
      DEapp (eff_dterm muc denv e1, eff_dterm muc denv e2)
  | Ptree.Tscope (q, e1) ->
      let muc = open_scope muc "dummy" in
      let muc = import_scope muc (string_list_of_qualid q) in
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      DEattr (eff_dterm muc denv e1, Sattr.empty)
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  | Ptree.Tasref q ->
      let e1 = { term_desc = Tident q; term_loc = loc } in
      let d1 = eff_dterm muc denv e1 in
      DEattr (undereference d1, Sattr.empty)