X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_refiner%2FnCicUnification.ml;h=8e84c015dbed4c19508b876409678e03e523f22e;hb=8e0e2b06cfc3fb3116e1fce632d9897fdbac9895;hp=5353363d507bcbac84e6e939daa89dc0a343c038;hpb=5858c6b8895010b580b6d7be26a962e7ed74cce4;p=helm.git diff --git a/helm/software/components/ng_refiner/nCicUnification.ml b/helm/software/components/ng_refiner/nCicUnification.ml index 5353363d5..8e84c015d 100644 --- a/helm/software/components/ng_refiner/nCicUnification.ml +++ b/helm/software/components/ng_refiner/nCicUnification.ml @@ -14,20 +14,17 @@ exception UnificationFailure of string Lazy.t;; exception Uncertain of string Lazy.t;; exception AssertFailure of string Lazy.t;; +exception KeepReducing of string Lazy.t;; +exception KeepReducingThis of + string Lazy.t * (NCicReduction.machine * bool) * + (NCicReduction.machine * bool) ;; let (===) x y = Pervasives.compare x y = 0 ;; -let uncert_exc metasenv subst context t1 t2 = - Uncertain (lazy ( +let mk_msg metasenv subst context t1 t2 = + (lazy ( "Can't unify " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " with " ^ NCicPp.ppterm ~metasenv ~subst ~context t2)) -;; - -let fail_exc metasenv subst context t1 t2 = - UnificationFailure (lazy ( - "Can't unify " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^ - " with " ^ NCicPp.ppterm ~metasenv ~subst ~context t2)); -;; let mk_appl ~upto hd tl = NCicReduction.head_beta_reduce ~upto @@ -80,23 +77,35 @@ module Ref = NReference;; let debug = ref false;; let indent = ref "";; +let times = ref [];; let pp s = if !debug then prerr_endline (Printf.sprintf "%-20s" !indent ^ " " ^ Lazy.force s) - else - () ;; let inside c = - indent := !indent ^ String.make 1 c; - if !debug then prerr_endline ("{{{" ^ !indent ^ " ") + if !debug then + begin + let time1 = Unix.gettimeofday () in + indent := !indent ^ String.make 1 c; + times := time1 :: !times; + prerr_endline ("{{{" ^ !indent ^ " ") + end ;; -let outside ok = - if !debug then prerr_endline "}}}"; - if not ok then pp (lazy "exception raised!"); - try - indent := String.sub !indent 0 (String.length !indent -1) - with - Invalid_argument _ -> indent := "??"; () +let outside exc_opt = + if !debug then + begin + let time2 = Unix.gettimeofday () in + let time1 = + match !times with time1::tl -> times := tl; time1 | [] -> assert false in + prerr_endline ("}}} " ^ string_of_float (time2 -. time1)); + (match exc_opt with + | Some e -> prerr_endline ("exception raised: " ^ Printexc.to_string e) + | None -> ()); + try + indent := String.sub !indent 0 (String.length !indent -1) + with + Invalid_argument _ -> indent := "??"; () + end ;; let ppcontext ~metasenv ~subst c = @@ -152,47 +161,26 @@ let rec could_reduce = | C.Appl [] | C.LetIn _ | C.Implicit _ -> assert false ;; -let rec lambda_intros rdb metasenv subst context t args = - let tty = NCicTypeChecker.typeof ~metasenv ~subst context t in - let argsty = - List.map - (fun arg -> arg, NCicTypeChecker.typeof ~metasenv ~subst context arg) args in - let context_of_args = context in - let rec mk_lambda metasenv subst context n processed_args = function - | [] -> +let rec lambda_intros rdb metasenv subst context argsno ty = + pp (lazy ("LAMBDA INTROS: " ^ NCicPp.ppterm ~metasenv ~subst ~context ty)); + match argsno with + 0 -> let metasenv, _, bo, _ = - NCicMetaSubst.mk_meta metasenv context - (`WithType (NCicSubstitution.lift n tty)) + NCicMetaSubst.mk_meta metasenv context (`WithType ty) in - metasenv, subst, bo - | (arg,ty)::tail -> - pp(lazy("arg{ " ^ - NCicPp.ppterm ~metasenv ~subst ~context:context_of_args arg ^ " : " ^ - NCicPp.ppterm ~metasenv ~subst ~context:context_of_args ty)); - let metasenv, subst, telescopic_ty = - if processed_args = [] then metasenv, subst, ty else - let _ = pp(lazy("delift")) in - delift_type_wrt_terms rdb metasenv subst context - (NCicSubstitution.lift n ty) - (List.map (NCicSubstitution.lift n) (List.rev processed_args)) - in - pp(lazy("arg} "^NCicPp.ppterm ~metasenv ~subst ~context telescopic_ty)); - let name = "HBeta"^string_of_int n in - let metasenv, subst, bo = - mk_lambda metasenv subst ((name,NCic.Decl telescopic_ty)::context) (n+1) - (arg::processed_args) tail - in - metasenv, subst, NCic.Lambda (name, telescopic_ty, bo) - in - pp(lazy("LAMBDA_INTROS{ " ^ - NCicPp.ppterm ~metasenv ~subst ~context t ^ ":" ^ - NCicPp.ppterm ~metasenv ~subst ~context tty ^ " over " ^ - String.concat "," (List.map (NCicPp.ppterm ~metasenv ~subst ~context)args))); - let rc = mk_lambda metasenv subst context 0 [] argsty in - pp(lazy("LAMBDA_INTROS}")); - rc - -and instantiate rdb test_eq_only metasenv subst context n lc t swap = + metasenv, bo + | _ -> + (match NCicReduction.whd ~subst context ty with + C.Prod (n,so,ta) -> + let metasenv,bo = + lambda_intros rdb metasenv subst + ((n,C.Decl so)::context) (argsno - 1) ta + in + metasenv,C.Lambda (n,so,bo) + | _ -> assert false) +;; + +let rec instantiate rdb test_eq_only metasenv subst context n lc t swap = (*D*) inside 'I'; try let rc = pp (lazy(string_of_int n ^ " :=?= "^ NCicPp.ppterm ~metasenv ~subst ~context t)); @@ -210,7 +198,9 @@ and instantiate rdb test_eq_only metasenv subst context n lc t swap = assert(has_tag ((=)`IsSort) tags); metasenv, subst, t | _ -> - let exc_to_be = fail_exc metasenv subst context (NCic.Meta (n,lc)) t in + let exc_to_be = + UnificationFailure (mk_msg metasenv subst context (NCic.Meta (n,lc)) t) + in let t, ty_t = try t, NCicTypeChecker.typeof ~subst ~metasenv context t with @@ -275,8 +265,9 @@ and instantiate rdb test_eq_only metasenv subst context n lc t swap = let metasenv = List.filter (fun x,_ -> i <> x) metasenv in metasenv, subst, m, j | NCic.Appl (NCic.Meta _ as hd :: args) as t -> - let metasenv, subst, lambda_Mj = - lambda_intros rdb metasenv subst context t args + let metasenv, lambda_Mj = + lambda_intros rdb metasenv subst context (List.length args) + (NCicTypeChecker.typeof ~metasenv ~subst context hd) in let metasenv,subst= unify true metasenv subst context hd lambda_Mj in let t = NCicReduction.whd ~subst context t in @@ -352,15 +343,18 @@ and instantiate rdb test_eq_only metasenv subst context n lc t swap = List.filter (fun (m,_) -> not (n = m)) metasenv in metasenv, subst - (*D*) in outside true; rc with exn -> outside false; raise exn + (*D*) in outside None; rc with exn -> outside (Some exn); raise exn and unify rdb test_eq_only metasenv subst context t1 t2 = (*D*) inside 'U'; try let rc = - let fo_unif test_eq_only metasenv subst t1 t2 = + let fo_unif test_eq_only metasenv subst (norm1,t1) (norm2,t2) = (*D*) inside 'F'; try let rc = pp (lazy(" " ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " ==?== " ^ NCicPp.ppterm ~metasenv ~subst ~context t2 ^ ppmetasenv ~subst metasenv)); + pp (lazy(" " ^ NCicPp.ppterm ~metasenv ~subst:[] ~context t1 ^ " ==??== " ^ + NCicPp.ppterm ~metasenv ~subst:[] ~context t2 ^ ppmetasenv + ~subst metasenv)); if t1 === t2 then metasenv, subst else @@ -371,13 +365,13 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = assert false | (C.Sort (C.Type a), C.Sort (C.Type b)) when not test_eq_only -> if NCicEnvironment.universe_leq a b then metasenv, subst - else raise (fail_exc metasenv subst context t1 t2) + else raise (UnificationFailure (mk_msg metasenv subst context t1 t2)) | (C.Sort (C.Type a), C.Sort (C.Type b)) -> if NCicEnvironment.universe_eq a b then metasenv, subst - else raise (fail_exc metasenv subst context t1 t2) + else raise (UnificationFailure (mk_msg metasenv subst context t1 t2)) | (C.Sort C.Prop,C.Sort (C.Type _)) -> if (not test_eq_only) then metasenv, subst - else raise (fail_exc metasenv subst context t1 t2) + else raise (UnificationFailure (mk_msg metasenv subst context t1 t2)) | (C.Lambda (name1,s1,t1), C.Lambda(_,s2,t2)) | (C.Prod (name1,s1,t1), C.Prod(_,s2,t2)) -> @@ -421,13 +415,24 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = let term2 = NCicSubstitution.subst_meta lc2 term in unify rdb test_eq_only metasenv subst context term1 term2 with NCicUtils.Subst_not_found _-> raise (UnificationFailure msg)) + + | NCic.Appl (NCic.Meta (i,_)::_ as l1), + NCic.Appl (NCic.Meta (j,_)::_ as l2) when i=j -> + (try + List.fold_left2 + (fun (metasenv, subst) t1 t2 -> + unify rdb test_eq_only metasenv subst context t1 t2) + (metasenv,subst) l1 l2 + with Invalid_argument _ -> + raise (UnificationFailure (mk_msg metasenv subst context t1 t2))) | _, NCic.Meta (n, _) when is_locked n subst -> (let (metasenv, subst), i = match NCicReduction.whd ~subst context t1 with - | NCic.Appl (NCic.Meta (i,l)::args) -> - let metasenv, subst, lambda_Mj = - lambda_intros rdb metasenv subst context t1 args + | NCic.Appl (NCic.Meta (i,l) as meta :: args) -> + let metasenv, lambda_Mj = + lambda_intros rdb metasenv subst context (List.length args) + (NCicTypeChecker.typeof ~metasenv ~subst context meta) in unify rdb test_eq_only metasenv subst context (C.Meta (i,l)) lambda_Mj, @@ -462,23 +467,15 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = metasenv, ((i, (name, ctx, term, ty)) :: subst) with Not_found -> assert false)) - | C.Meta (n,lc), t -> - (try - let _,_,term,_ = NCicUtils.lookup_subst n subst in - let term = NCicSubstitution.subst_meta lc term in - unify rdb test_eq_only metasenv subst context term t - with NCicUtils.Subst_not_found _-> - instantiate rdb test_eq_only metasenv subst context n lc - (NCicReduction.head_beta_reduce ~subst t) false) + | C.Meta (n,lc), t when List.mem_assoc n subst -> + let _,_,term,_ = NCicUtils.lookup_subst n subst in + let term = NCicSubstitution.subst_meta lc term in + unify rdb test_eq_only metasenv subst context term t - | t, C.Meta (n,lc) -> - (try - let _,_,term,_ = NCicUtils.lookup_subst n subst in - let term = NCicSubstitution.subst_meta lc term in - unify rdb test_eq_only metasenv subst context t term - with NCicUtils.Subst_not_found _-> - instantiate rdb test_eq_only metasenv subst context n lc - (NCicReduction.head_beta_reduce ~subst t) true) + | t, C.Meta (n,lc) when List.mem_assoc n subst -> + let _,_,term,_ = NCicUtils.lookup_subst n subst in + let term = NCicSubstitution.subst_meta lc term in + unify rdb test_eq_only metasenv subst context t term | NCic.Appl (NCic.Meta (i,l)::args), _ when List.mem_assoc i subst -> let _,_,term,_ = NCicUtils.lookup_subst i subst in @@ -492,23 +489,26 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = unify rdb test_eq_only metasenv subst context t1 (mk_appl ~upto:(List.length args) term args) - | NCic.Appl (NCic.Meta (i,_)::_ as l1), - NCic.Appl (NCic.Meta (j,_)::_ as l2) when i=j -> - (try - List.fold_left2 - (fun (metasenv, subst) t1 t2 -> - unify rdb test_eq_only metasenv subst context t1 t2) - (metasenv,subst) l1 l2 - with Invalid_argument _ -> - raise (fail_exc metasenv subst context t1 t2)) + | C.Meta (n,lc), t -> + instantiate rdb test_eq_only metasenv subst context n lc + (NCicReduction.head_beta_reduce ~subst t) false - | NCic.Appl (NCic.Meta (i,l)::args), _ -> - let metasenv, subst, lambda_Mj = - lambda_intros rdb metasenv subst context t1 args + | t, C.Meta (n,lc) -> + instantiate rdb test_eq_only metasenv subst context n lc + (NCicReduction.head_beta_reduce ~subst t) true + + | NCic.Appl (NCic.Meta (i,l) as meta :: args), _ -> + let metasenv, lambda_Mj = + lambda_intros rdb metasenv subst context (List.length args) + (NCicTypeChecker.typeof ~metasenv ~subst context meta) in let metasenv, subst = + try unify rdb test_eq_only metasenv subst context (C.Meta (i,l)) lambda_Mj + with UnificationFailure msg | Uncertain msg when not norm2-> + (* failure: let's try again argument vs argument *) + raise (KeepReducing msg) in let metasenv, subst = unify rdb test_eq_only metasenv subst context t1 t2 @@ -520,13 +520,18 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = metasenv, ((i, (name, ctx, term, ty)) :: subst) with Not_found -> assert false) - | _, NCic.Appl (NCic.Meta (i,l)::args) -> - let metasenv, subst, lambda_Mj = - lambda_intros rdb metasenv subst context t2 args + | _, NCic.Appl (NCic.Meta (i,l) as meta :: args) -> + let metasenv, lambda_Mj = + lambda_intros rdb metasenv subst context (List.length args) + (NCicTypeChecker.typeof ~metasenv ~subst context meta) in let metasenv, subst = + try unify rdb test_eq_only metasenv subst context lambda_Mj (C.Meta (i,l)) + with UnificationFailure msg | Uncertain msg when not norm1 -> + (* failure: let's try again argument vs argument *) + raise (KeepReducing msg) in let metasenv, subst = unify rdb test_eq_only metasenv subst context t1 t2 @@ -542,15 +547,6 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = | (C.Appl ((C.Const r1) as _hd1::tl1), C.Appl (C.Const r2::tl2)) when Ref.eq r1 r2 -> let relevance = NCicEnvironment.get_relevance r1 in - let relevance = match r1 with - | Ref.Ref (_,Ref.Con (_,_,lno)) -> - let relevance = - try snd (HExtlib.split_nth lno relevance) - with Failure _ -> [] - in - HExtlib.mk_list false lno @ relevance - | _ -> relevance - in let metasenv, subst, _ = try List.fold_left2 @@ -564,8 +560,12 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = in metasenv, subst, relevance) (metasenv, subst, relevance) tl1 tl2 - with Invalid_argument _ -> - raise (uncert_exc metasenv subst context t1 t2) + with + Invalid_argument _ -> + raise (Uncertain (mk_msg metasenv subst context t1 t2)) + | UnificationFailure _ | Uncertain _ when not (norm1 && norm2) -> + raise (KeepReducing (mk_msg metasenv subst context t1 t2)) + | KeepReducing _ | KeepReducingThis _ -> assert false in metasenv, subst @@ -587,7 +587,7 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = | _ -> false in if not (Ref.eq ref1 ref2) then - raise (uncert_exc metasenv subst context t1 t2) + raise (Uncertain (mk_msg metasenv subst context t1 t2)) else let metasenv, subst = unify rdb test_eq_only metasenv subst context outtype1 outtype2 in @@ -603,13 +603,15 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = (metasenv, subst) pl1 pl2 with Invalid_argument _ -> assert false) | (C.Implicit _, _) | (_, C.Implicit _) -> assert false - | _ when NCicUntrusted.metas_of_term subst context t1 = [] && - NCicUntrusted.metas_of_term subst context t2 = [] -> - raise (fail_exc metasenv subst context t1 t2) - | _ -> raise (uncert_exc metasenv subst context t1 t2) - (*D*) in outside true; rc with exn -> outside false; raise exn + | _ when norm1 && norm2 -> + if (could_reduce t1 || could_reduce t2) then + raise (Uncertain (mk_msg metasenv subst context t1 t2)) + else + raise (UnificationFailure (mk_msg metasenv subst context t1 t2)) + | _ -> raise (KeepReducing (mk_msg metasenv subst context t1 t2)) + (*D*) in outside None; rc with exn -> outside (Some exn); raise exn in - let try_hints metasenv subst t1 t2 (* exc*) = + let try_hints metasenv subst (_,t1 as mt1) (_,t2 as mt2) (* exc*) = (*D*) inside 'H'; try let rc = pp(lazy ("\nProblema:\n" ^ NCicPp.ppterm ~metasenv ~subst ~context t1 ^ " =?= " ^ @@ -632,9 +634,9 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = try (*D*) inside 'K'; try let rc = let metasenv,subst = - fo_unif test_eq_only metasenv subst t1 c1 in + fo_unif test_eq_only metasenv subst mt1 (false,c1) in let metasenv,subst = - fo_unif test_eq_only metasenv subst c2 t2 in + fo_unif test_eq_only metasenv subst (false,c2) mt2 in let metasenv,subst = List.fold_left (fun (metasenv, subst) (x,y) -> @@ -643,13 +645,36 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = in pp(lazy("FUNZIONA!")); Some (metasenv, subst) - (*D*) in outside true; rc with exn -> outside false; raise exn + (*D*) in outside None; rc with exn -> outside (Some exn); raise exn with - UnificationFailure _ | Uncertain _ -> - cand_iter tl + KeepReducing _ | UnificationFailure _ | Uncertain _ -> cand_iter tl + | KeepReducingThis _ -> assert false in cand_iter candidates - (*D*) in outside true; rc with exn -> outside false; raise exn + (*D*) in outside None; rc with exn -> outside (Some exn); raise exn + in + let put_in_whd m1 m2 = + NCicReduction.reduce_machine ~delta:max_int ~subst context m1, + NCicReduction.reduce_machine ~delta:max_int ~subst context m2 + in + let fo_unif_w_hints test_eq_only metasenv subst (xx1,t1 as m1) (xx2,t2 as m2) = + try fo_unif test_eq_only metasenv subst m1 m2 + with + | UnificationFailure _ as exn -> raise exn + | KeepReducing _ | Uncertain _ as exn -> + let (t1,norm1 as tm1),(t2,norm2 as tm2) = + put_in_whd (0,[],t1,[]) (0,[],t2,[]) + in + match + try_hints metasenv subst + (norm1,NCicReduction.unwind t1) (norm2,NCicReduction.unwind t2) + with + | Some x -> x + | None -> + match exn with + | KeepReducing msg -> raise (KeepReducingThis (msg,tm1,tm2)) + | Uncertain _ as exn -> raise exn + | _ -> assert false in let height_of = function | NCic.Const (Ref.Ref (_,Ref.Def h)) @@ -658,18 +683,14 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = | NCic.Appl(NCic.Const(Ref.Ref(_,Ref.Fix (_,_,h)))::_) -> h | _ -> 0 in - let put_in_whd m1 m2 = - NCicReduction.reduce_machine ~delta:max_int ~subst context m1, - NCicReduction.reduce_machine ~delta:max_int ~subst context m2 - in let small_delta_step ~subst ((_,_,t1,_ as m1, norm1) as x1) ((_,_,t2,_ as m2, norm2) as x2) = assert (not (norm1 && norm2)); if norm1 then - x1,NCicReduction.reduce_machine ~delta:(height_of t2 -1) ~subst context m2 + x1,NCicReduction.reduce_machine ~delta:0 ~subst context m2 else if norm2 then - NCicReduction.reduce_machine ~delta:(height_of t1 -1) ~subst context m1,x2 + NCicReduction.reduce_machine ~delta:0 ~subst context m1,x2 else let h1 = height_of t1 in let h2 = height_of t2 in @@ -687,7 +708,7 @@ and unify rdb test_eq_only metasenv subst context t1 t2 = " === " ^ NCicPp.ppterm ~metasenv ~subst ~context (NCicReduction.unwind (k2,e2,t2,s2)))); -pp (lazy (string_of_bool norm1 ^ " ?? " ^ string_of_bool norm2)); + pp (lazy (string_of_bool norm1 ^ " ?? " ^ string_of_bool norm2)); let relevance = [] (* TO BE UNDERSTOOD match t1 with | C.Const r -> NCicEnvironment.get_relevance r @@ -711,43 +732,37 @@ pp (lazy (string_of_bool norm1 ^ " ?? " ^ string_of_bool norm2)); in let hh1,hh2,todo=check_stack (List.rev s1) (List.rev s2) relevance [] in try - let metasenv,subst = fo_unif test_eq_only metasenv subst hh1 hh2 in + let metasenv,subst = + fo_unif_w_hints test_eq_only metasenv subst (norm1,hh1) (norm2,hh2) in List.fold_left (fun (metasenv,subst) (x1,x2,r) -> unif_from_stack x1 x2 r metasenv subst ) (metasenv,subst) todo - with UnificationFailure _ | Uncertain _ when not (norm1 && norm2) -> + with + | KeepReducing _ -> assert false + | KeepReducingThis _ -> + assert (not (norm1 && norm2)); unif_machines metasenv subst (small_delta_step ~subst m1 m2) - (*D*) in outside true; rc with exn -> outside false; raise exn + | UnificationFailure _ | Uncertain _ when (not (norm1 && norm2)) + -> unif_machines metasenv subst (small_delta_step ~subst m1 m2) + | UnificationFailure msg + when could_reduce (NCicReduction.unwind (fst m1)) + || could_reduce (NCicReduction.unwind (fst m2)) + -> raise (Uncertain msg) + (*D*) in outside None; rc with exn -> outside (Some exn); raise exn in - try fo_unif test_eq_only metasenv subst t1 t2 - with - | UnificationFailure msg as exn -> - (try - unif_machines metasenv subst - (put_in_whd (0,[],t1,[]) (0,[],t2,[])) - with - | UnificationFailure _ -> raise (UnificationFailure msg) - | Uncertain _ -> raise exn) - | Uncertain msg as exn -> -(* - prerr_endline "PROBLEMA"; - prerr_endline (NCicPp.ppterm ~metasenv ~subst ~context t1); - prerr_endline (NCicPp.ppterm ~metasenv ~subst ~context t2); -*) - let (t1,_ as t1m),(t2,_ as t2m) = put_in_whd (0,[],t1,[]) (0,[],t2,[]) in - match - try_hints metasenv subst - (NCicReduction.unwind t1) (NCicReduction.unwind t2) - with - | Some x -> x - | None -> - try - unif_machines metasenv subst (t1m, t2m) + try fo_unif_w_hints test_eq_only metasenv subst (false,t1) (false,t2) + with + | KeepReducingThis (msg,tm1,tm2) -> + (try + unif_machines metasenv subst (tm1,tm2) with | UnificationFailure _ -> raise (UnificationFailure msg) - | Uncertain _ -> raise exn - (*D*) in outside true; rc with exn -> outside false; raise exn + | Uncertain _ -> raise (Uncertain msg) + | KeepReducing _ -> assert false) + | KeepReducing _ -> assert false + + (*D*) in outside None; rc with KeepReducing _ -> assert false | exn -> outside (Some exn); raise exn and delift_type_wrt_terms rdb metasenv subst context t args = let lc = List.rev args @ mk_irl (List.length context) (List.length args+1) in @@ -762,7 +777,9 @@ and delift_type_wrt_terms rdb metasenv subst context t args = in indent := ind; res) metasenv subst context 0 (0,NCic.Ctx lc) t - with NCicMetaSubst.MetaSubstFailure _ -> (metasenv, subst), t + with + NCicMetaSubst.MetaSubstFailure _ + | NCicMetaSubst.Uncertain _ -> (metasenv, subst), t in metasenv, subst, t ;;