X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_refiner%2FnCicRefiner.ml;h=c3765f3f0261eb092bbb93e87c8e12df6d0a9bc7;hb=8e0e2b06cfc3fb3116e1fce632d9897fdbac9895;hp=0f835961eeaef5353edd1eafa6110b8ee47e234f;hpb=dcdbb979433a61e2ef2842d96604098728824416;p=helm.git

diff --git a/helm/software/components/ng_refiner/nCicRefiner.ml b/helm/software/components/ng_refiner/nCicRefiner.ml
index 0f835961e..c3765f3f0 100644
--- a/helm/software/components/ng_refiner/nCicRefiner.ml
+++ b/helm/software/components/ng_refiner/nCicRefiner.ml
@@ -18,16 +18,37 @@ exception AssertFailure of string Lazy.t;;
 module C = NCic
 module Ref = NReference
 
+let debug = ref false;;
 let indent = ref "";;
-let inside c = indent := !indent ^ String.make 1 c;;
-let outside () = indent := String.sub !indent 0 (String.length !indent -1);;
-
-
-let pp s = 
+let times = ref [];;
+let pp s =
+ if !debug then
   prerr_endline (Printf.sprintf "%-20s" !indent ^ " " ^ Lazy.force s)
-;;  
+;;
+let inside c =
+ 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
+  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));
+   if not ok then prerr_endline "exception raised!";
+   try
+    indent := String.sub !indent 0 (String.length !indent -1)
+   with
+    Invalid_argument _ -> indent := "??"; ()
+ end
+;;
 
-let pp _ = ();;
 
 let wrap_exc msg = function
   | NCicUnification.Uncertain _ -> Uncertain msg
@@ -36,16 +57,40 @@ let wrap_exc msg = function
   | e -> raise e
 ;;
 
-let exp_implicit metasenv context expty =
- let foo x = match expty with Some t -> `WithType t | None -> x in
+let exp_implicit rdb ~localise metasenv subst context expty t =
+ let foo x = function Some t -> `WithType t | None -> x in
  function      
-  | `Closed -> NCicMetaSubst.mk_meta metasenv [] (foo `Term)
-  | `Type -> NCicMetaSubst.mk_meta metasenv context (foo `Type)
-  | `Term -> NCicMetaSubst.mk_meta metasenv context (foo `Term)
+  | `Closed ->
+      let metasenv,subst,expty =
+       match expty with
+          None -> metasenv,subst,None
+        | Some typ ->
+           let (metasenv,subst),typ =
+            try
+             NCicMetaSubst.delift
+              ~unify:(fun m s c t1 t2 ->
+                try Some (NCicUnification.unify rdb m s c t1 t2)
+                with NCicUnification.UnificationFailure _ | NCicUnification.Uncertain _ -> None)
+              metasenv subst context 0 (0,NCic.Irl 0) typ
+            with
+              NCicMetaSubst.MetaSubstFailure _
+            | NCicMetaSubst.Uncertain _ ->
+               raise (RefineFailure (lazy (localise t,"Trying to create a closed meta with a non closed type")))
+
+           in
+            metasenv,subst,Some typ
+      in
+       NCicMetaSubst.mk_meta metasenv [] (foo `Term expty),subst
+  | `Type -> NCicMetaSubst.mk_meta metasenv context (foo `Type expty),subst
+  | `Term -> NCicMetaSubst.mk_meta metasenv context (foo `Term expty),subst
+  | `Tagged s ->
+      NCicMetaSubst.mk_meta ~attrs:[`Name s] metasenv context (foo `Term expty),subst
+  | `Vector ->
+      raise (RefineFailure (lazy (localise t, "A vector of implicit terms " ^
+       "can only be used in argument position")))
   | _ -> assert false
 ;;
 
-
 let check_allowed_sort_elimination rdb localise r orig =
    let mkapp he arg =
      match he with
@@ -89,7 +134,7 @@ let check_allowed_sort_elimination rdb localise r orig =
         with exc -> raise (wrap_exc (lazy (localise orig, 
           "Sort elimination not allowed ")) exc))
      | _ -> assert false
-     (*D*)in outside(); rc with exc -> outside (); raise exc
+     (*D*)in outside true; rc with exc -> outside false; raise exc
    in
     aux
 ;;
@@ -98,35 +143,39 @@ let rec typeof rdb
   ?(localise=fun _ -> Stdpp.dummy_loc) 
   metasenv subst context term expty 
 =
-  let force_ty skip_lambda metasenv subst context orig t infty expty =
+  let force_ty skip_lambda skip_appl metasenv subst context orig t infty expty =
     (*D*)inside 'F'; try let rc = 
     match expty with
     | Some expty ->
        (match t with
        | C.Implicit _ -> assert false
        | C.Lambda _ when skip_lambda -> metasenv, subst, t, expty
+       | C.Appl _ when skip_appl -> metasenv, subst, t, expty
        | _ ->
-          pp (lazy (
+          pp (lazy ("forcing infty=expty: "^
           (NCicPp.ppterm ~metasenv ~subst ~context infty) ^  " === " ^
           (NCicPp.ppterm ~metasenv ~subst:[] ~context expty)));
            try 
              let metasenv, subst =
+    (*D*)inside 'U'; try let rc = 
                NCicUnification.unify rdb metasenv subst context infty expty 
+    (*D*)in outside true; rc with exc -> outside false; raise exc
              in
              metasenv, subst, t, expty
-           with exc -> 
+           with 
+           | NCicUnification.Uncertain _ 
+           | NCicUnification.UnificationFailure _ as exc -> 
              try_coercions rdb ~localise 
                metasenv subst context t orig infty expty true exc)
     | None -> metasenv, subst, t, infty
-    (*D*)in outside(); rc with exc -> outside (); raise exc
+    (*D*)in outside true; rc with exc -> outside false; raise exc
   in
   let rec typeof_aux metasenv subst context expty = 
     fun t as orig -> 
     (*D*)inside 'R'; try let rc = 
-    pp (lazy (NCicPp.ppterm ~metasenv ~subst ~context t));
-    pp (lazy (if expty = None then "NONE" else "SOME"));
-    if (List.exists (fun (i,_) -> i=29) subst) then 
-      pp (lazy (NCicPp.ppsubst ~metasenv subst));
+    pp (lazy (NCicPp.ppterm ~metasenv ~subst ~context t ^ " ::exp:: " ^
+       match expty with None -> "None" | Some e -> 
+       NCicPp.ppterm ~metasenv ~subst ~context e));
     let metasenv, subst, t, infty = 
     match t with
     | C.Rel n ->
@@ -139,14 +188,17 @@ let rec typeof rdb
            raise (RefineFailure (lazy (localise t,"unbound variable"))))
         in
         metasenv, subst, t, infty
-    | C.Sort (C.Type [false,u]) -> metasenv,subst,t,(C.Sort (C.Type [true, u]))
-    | C.Sort (C.Type _) -> 
-        raise (AssertFailure (lazy ("Cannot type an inferred type: "^
-          NCicPp.ppterm ~subst ~metasenv ~context t)))
-    | C.Sort _ -> metasenv,subst,t,(C.Sort (C.Type NCicEnvironment.type0))
+    | C.Sort s -> 
+         (try metasenv, subst, t, C.Sort (NCicEnvironment.typeof_sort s)
+         with 
+         | NCicEnvironment.UntypableSort msg -> 
+              raise (RefineFailure (lazy (localise t, Lazy.force msg)))
+         | NCicEnvironment.AssertFailure msg -> raise (AssertFailure msg))
     | C.Implicit infos -> 
-         let metasenv,_,t,ty = exp_implicit metasenv context expty infos in
-         metasenv, subst, t, ty 
+         let (metasenv,_,t,ty),subst =
+           exp_implicit rdb ~localise metasenv subst context expty t infos
+         in
+          metasenv, subst, t, ty 
     | C.Meta (n,l) as t -> 
        let ty =
         try
@@ -197,7 +249,10 @@ let rec typeof rdb
        let (metasenv,subst), exp_ty_t = 
          match exp_s with 
          | Some exp_s -> 
-             (try NCicUnification.unify rdb metasenv subst context s exp_s,exp_ty_t
+             (try 
+               pp(lazy("Force source to: "^NCicPp.ppterm ~metasenv ~subst
+                  ~context exp_s));
+               NCicUnification.unify rdb metasenv subst context s exp_s,exp_ty_t
              with exc -> raise (wrap_exc (lazy (localise orig_s, Printf.sprintf
                "Source type %s was expected to be %s" (NCicPp.ppterm ~metasenv
                ~subst ~context s) (NCicPp.ppterm ~metasenv ~subst ~context
@@ -209,7 +264,7 @@ let rec typeof rdb
          typeof_aux metasenv subst context_for_t exp_ty_t t 
        in
        if force_after then
-         force_ty false metasenv subst context orig 
+         force_ty false true metasenv subst context orig 
            (C.Lambda(n,s,t)) (C.Prod (n,s,ty_t)) expty
        else 
          metasenv, subst, C.Lambda(n,s,t), C.Prod (n,s,ty_t)
@@ -222,23 +277,44 @@ let rec typeof rdb
        let metasenv, subst, t, _ = 
          typeof_aux metasenv subst context (Some ty) t in
        let context1 = (n, C.Def (t,ty)) :: context in
+       let metasenv, subst, expty1 = 
+         match expty with 
+         | None -> metasenv, subst, None 
+         | Some x -> 
+             let m, s, x = 
+               NCicUnification.delift_type_wrt_terms 
+                rdb metasenv subst context1 (NCicSubstitution.lift 1 x)
+                [NCicSubstitution.lift 1 t]
+             in
+               m, s, Some x
+       in
        let metasenv, subst, bo, bo_ty = 
-         typeof_aux metasenv subst context1 None bo 
+         typeof_aux metasenv subst context1 expty1 bo 
        in
        let bo_ty = NCicSubstitution.subst ~avoid_beta_redexes:true t bo_ty in
        metasenv, subst, C.LetIn (n, ty, t, bo), bo_ty
     | C.Appl ((he as orig_he)::(_::_ as args)) ->
-       let upto = 
-         match orig_he with C.Meta _ -> List.length args | _ -> 0
+       let upto = match orig_he with C.Meta _ -> List.length args | _ -> 0 in
+       let hbr t = 
+         if upto > 0 then NCicReduction.head_beta_reduce ~upto t else t 
        in
-       let metasenv, subst, he, ty_he = 
-         typeof_aux metasenv subst context None he in
-       let metasenv, subst, t, ty = 
-         eat_prods rdb ~localise
-           metasenv subst context orig_he he ty_he args
+       let refine_appl () =
+         let metasenv, subst, he, ty_he = 
+            typeof_aux metasenv subst context None he in
+         let metasenv, subst, t, ty = 
+           eat_prods rdb ~localise force_ty metasenv subst context expty t
+            orig_he he ty_he args in
+         metasenv, subst, hbr t, ty
        in
-       let t = if upto > 0 then NCicReduction.head_beta_reduce ~upto t else t in
-       metasenv, subst, t, ty
+       if args = [C.Implicit `Vector] && expty <> None then
+         (* we try here to expand the vector a 0 implicits, but we use
+          * the expected type *)
+         try
+           let metasenv, subst, he, ty_he = 
+              typeof_aux metasenv subst context expty he in
+           metasenv, subst, hbr he, ty_he
+         with Uncertain _ | RefineFailure _ -> refine_appl ()
+       else refine_appl ()
    | C.Appl _ -> raise (AssertFailure (lazy "Appl of length < 2"))
    | C.Match (Ref.Ref (_,Ref.Ind (_,tyno,_)) as r,
           outtype,(term as orig_term),pl) as orig ->
@@ -276,7 +352,7 @@ let rec typeof rdb
       let metasenv =
        List.filter (function (j,_) -> j <> metanoouttype) metasenv in
       let subst =
-       (metanoouttype,(Some "outtype",context,outtype,metaoutsort))::subst in
+       (metanoouttype,([`Name "outtype"],context,outtype,metaoutsort))::subst in
       let outtype = newouttype in
 
       (* let's control if the sort elimination is allowed: [(I q1 ... qr)|B] *)
@@ -315,7 +391,7 @@ let rec typeof rdb
                 NCicTypeChecker.type_of_branch 
                   ~subst context leftno outtype cons ty_cons in
               pp (lazy ("TYPEOFBRANCH: " ^
-               NCicPp.ppterm ~metasenv ~subst ~context p ^ " ::: " ^
+               NCicPp.ppterm ~metasenv ~subst ~context p ^ " ::inf:: " ^
                NCicPp.ppterm ~metasenv ~subst ~context ty_branch ));
               let metasenv, subst, p, _ = 
                 typeof_aux metasenv subst context (Some ty_branch) p in
@@ -327,10 +403,10 @@ let rec typeof rdb
       metasenv, subst, C.Match (r, outtype, term, pl),resty
     | C.Match _ -> assert false
     in
-    pp (lazy (NCicPp.ppterm ~metasenv ~subst ~context t ^ " :: "^
+    pp (lazy (NCicPp.ppterm ~metasenv ~subst ~context t ^ " ::inf:: "^
          NCicPp.ppterm ~metasenv ~subst ~context infty ));
-      force_ty true metasenv subst context orig t infty expty
-    (*D*)in outside(); rc with exc -> outside (); raise exc
+      force_ty true true metasenv subst context orig t infty expty
+    (*D*)in outside true; rc with exc -> outside false; raise exc
   in
     typeof_aux metasenv subst context expty term
 
@@ -342,21 +418,22 @@ and try_coercions rdb
   let rec first exc = function
   | [] ->         
       raise (wrap_exc (lazy (localise orig_t, Printf.sprintf
-        "The term %s has type %s but is here used with type %s"
+        "The term\n%s\nhas type\n%s\nbut is here used with type\n%s"
         (NCicPp.ppterm ~metasenv ~subst ~context t)
         (NCicPp.ppterm ~metasenv ~subst ~context infty)
         (NCicPp.ppterm ~metasenv ~subst ~context expty))) exc)
-  | (metasenv, newterm, newtype, meta)::tl ->
+  | (_,metasenv, newterm, newtype, meta)::tl ->
       try 
+          pp (lazy("K=" ^ NCicPp.ppterm ~metasenv ~subst ~context newterm));
           pp (lazy ( "UNIFICATION in CTX:\n"^ 
             NCicPp.ppcontext ~metasenv ~subst context
             ^ "\nMENV: " ^
             NCicPp.ppmetasenv metasenv ~subst
             ^ "\nOF: " ^
-            NCicPp.ppterm ~metasenv ~subst ~context meta ^  " === " ^
-            NCicPp.ppterm ~metasenv ~subst ~context t ^ "\n"));
+            NCicPp.ppterm ~metasenv ~subst ~context t ^  " === " ^
+            NCicPp.ppterm ~metasenv ~subst ~context meta ^ "\n"));
         let metasenv, subst = 
-          NCicUnification.unify rdb metasenv subst context meta t
+          NCicUnification.unify rdb metasenv subst context t meta
         in
           pp (lazy ( "UNIFICATION in CTX:\n"^ 
             NCicPp.ppcontext ~metasenv ~subst context
@@ -375,9 +452,12 @@ and try_coercions rdb
       | NCicUnification.UnificationFailure _ -> first exc tl
       | NCicUnification.Uncertain _ as exc -> first exc tl
   in 
+  pp(lazy("try_coercion " ^ 
+    NCicPp.ppterm ~metasenv ~subst ~context infty ^ " |---> " ^
+    NCicPp.ppterm ~metasenv ~subst ~context expty));
     first exc
       (NCicCoercion.look_for_coercion 
-        rdb.NRstatus.coerc_db metasenv subst context infty expty)
+        rdb metasenv subst context infty expty)
 
 and force_to_sort rdb metasenv subst context t orig_t localise ty =
   match NCicReduction.whd ~subst context ty with
@@ -437,25 +517,51 @@ and guess_name subst ctx ty =
       with NCicUtils.Subst_not_found _ -> aux 'M')
   | _ -> aux 'H' 
 
-and eat_prods rdb
-  ~localise metasenv subst context orig_he he ty_he args 
-=
+and eat_prods rdb ~localise force_ty metasenv subst context expty orig_t orig_he he ty_he args =
   (*D*)inside 'E'; try let rc = 
-  let rec aux metasenv subst args_so_far he ty_he = function 
-  | []->metasenv, subst, NCicUntrusted.mk_appl he (List.rev args_so_far), ty_he
+  let rec aux metasenv subst args_so_far he ty_he xxx =
+  (*D*)inside 'V'; try let rc = 
+   match xxx with
+  | [] ->
+     let res = NCicUntrusted.mk_appl he (List.rev args_so_far) in
+     pp(lazy("FORCE FINAL APPL: " ^ 
+       NCicPp.ppterm ~metasenv ~subst ~context res ^
+       " of type " ^ NCicPp.ppterm ~metasenv ~subst ~context ty_he
+       ^ " to type " ^ match expty with None -> "None" | Some x -> 
+       NCicPp.ppterm ~metasenv ~subst ~context x));
+     (* whatever the term is, we force the type. in case of ((Lambda..) ?...)
+      * the application may also be a lambda! *)
+     force_ty false false metasenv subst context orig_t res ty_he expty
+  | NCic.Implicit `Vector::tl ->
+      let has_some_more_pis x =
+        match NCicReduction.whd ~subst context x with
+        |  NCic.Meta _ | NCic.Appl (NCic.Meta _::_) -> false
+        | _ -> true
+      in
+     (try
+       aux metasenv subst args_so_far he ty_he tl
+      with
+      | Uncertain _
+      | RefineFailure _ as exc when has_some_more_pis ty_he ->
+          (try
+           aux metasenv subst args_so_far he ty_he
+            (NCic.Implicit `Term :: NCic.Implicit `Vector :: tl)
+          with
+           Uncertain msg | RefineFailure msg -> raise (wrap_exc msg exc))
+     | RefineFailure msg when not (has_some_more_pis ty_he) ->
+        (* instantiating the head could change the has_some_more_pis flag *)
+        raise (Uncertain msg))
   | arg::tl ->
       match NCicReduction.whd ~subst context ty_he with 
       | C.Prod (_,s,t) ->
           let metasenv, subst, arg, _ = 
-            typeof rdb ~localise 
-              metasenv subst context arg (Some s) in
+            typeof rdb ~localise metasenv subst context arg (Some s) in
           let t = NCicSubstitution.subst ~avoid_beta_redexes:true arg t in
           aux metasenv subst (arg :: args_so_far) he t tl
       | C.Meta _
       | C.Appl (C.Meta _ :: _) as t ->
           let metasenv, subst, arg, ty_arg = 
-            typeof rdb ~localise 
-              metasenv subst context arg None in
+            typeof rdb ~localise metasenv subst context arg None in
           let name = guess_name subst context ty_arg in
           let metasenv, _, meta, _ = 
             NCicMetaSubst.mk_meta metasenv 
@@ -464,14 +570,15 @@ and eat_prods rdb
           let flex_prod = C.Prod (name, ty_arg, meta) in
           (* next line grants that ty_args is a type *)
           let metasenv,subst, flex_prod, _ =
-           typeof rdb ~localise metasenv subst
-            context flex_prod None in
+           typeof rdb ~localise metasenv subst context flex_prod None in
+(*
           pp (lazy ( "UNIFICATION in CTX:\n"^ 
             NCicPp.ppcontext ~metasenv ~subst context
             ^ "\nOF: " ^
             NCicPp.ppterm ~metasenv ~subst ~context t ^  " === " ^
             NCicPp.ppterm ~metasenv ~subst ~context flex_prod ^ "\n"));
-          let metasenv, subst = 
+*)
+          let metasenv, subst =
              try NCicUnification.unify rdb metasenv subst context t flex_prod 
              with exc -> raise (wrap_exc (lazy (localise orig_he, Printf.sprintf
               ("The term %s has an inferred type %s, but is applied to the" ^^
@@ -479,7 +586,11 @@ and eat_prods rdb
               (NCicPp.ppterm ~metasenv ~subst ~context he)
               (NCicPp.ppterm ~metasenv ~subst ~context t)
               (NCicPp.ppterm ~metasenv ~subst ~context arg)
-              (NCicPp.ppterm ~metasenv ~subst ~context ty_arg))) exc)
+              (NCicPp.ppterm ~metasenv ~subst ~context ty_arg))) 
+                 (match exc with
+                 | NCicUnification.UnificationFailure m -> 
+                     NCicUnification.Uncertain m
+                 | x -> x))
               (* XXX coerce to funclass *)
           in
           let meta = NCicSubstitution.subst ~avoid_beta_redexes:true arg meta in
@@ -502,7 +613,8 @@ and eat_prods rdb
                "only %d arguments") (NCicPp.ppterm ~metasenv ~subst ~context he)
                (List.length args) (List.length args_so_far))))
           in
-          aux metasenv subst [] newhead newheadty (arg :: tl)
+           aux metasenv subst [] newhead newheadty (arg :: tl)
+  (*D*)in outside true; rc with exc -> outside false; raise exc
   in
    (* We need to reverse the order of the new created metas since they
       are pushed on top of the metasenv in the wrong order *)
@@ -513,7 +625,7 @@ and eat_prods rdb
     List.partition (fun (i,_) -> i <= highest_meta) metasenv
    in
     (List.rev metasenv_new) @ metasenv_old, subst, newhead, newheadty
-  (*D*)in outside(); rc with exc -> outside (); raise exc
+  (*D*)in outside true; rc with exc -> outside false; raise exc
 ;;
 
 let rec first f l1 l2 =
@@ -559,7 +671,6 @@ let undebruijnate inductive ref t rev_fl =
 let typeof_obj 
   rdb ?(localise=fun _ -> Stdpp.dummy_loc) (uri,height,metasenv,subst,obj)
 = 
-prerr_endline ("===============\n" ^ NCicPp.ppobj (uri,height,metasenv,subst,obj));
   let check_type metasenv subst context (ty as orig_ty) =  (* XXX fattorizza *)
     let metasenv, subst, ty, sort = 
       typeof rdb ~localise metasenv subst context ty None
@@ -576,8 +687,7 @@ prerr_endline ("===============\n" ^ NCicPp.ppobj (uri,height,metasenv,subst,obj
          match bo with
          | Some bo ->
              let metasenv, subst, bo, ty = 
-               typeof rdb ~localise metasenv subst [] bo (Some ty)
-             in
+               typeof rdb ~localise metasenv subst [] bo (Some ty) in
              let height = (* XXX recalculate *) height in
                metasenv, subst, Some bo, ty, height
          | None -> metasenv, subst, None, ty, 0
@@ -590,7 +700,7 @@ prerr_endline ("===============\n" ^ NCicPp.ppobj (uri,height,metasenv,subst,obj
         List.fold_left
          (fun (types, metasenv, subst, fl) (relevance,name,k,ty,bo) ->
            let metasenv, subst, ty, _ = check_type metasenv subst [] ty in
-           let dbo = NCicTypeChecker.debruijn uri len [] bo in
+           let dbo = NCicTypeChecker.debruijn uri len [] ~subst bo in
            let localise = relocalise localise dbo bo in
             (name,C.Decl ty)::types,
               metasenv, subst, (relevance,name,k,ty,dbo,localise)::fl
@@ -639,7 +749,7 @@ prerr_endline ("===============\n" ^ NCicPp.ppobj (uri,height,metasenv,subst,obj
 	     let k_relev =
               try snd (HExtlib.split_nth leftno k_relev)
               with Failure _ -> k_relev in
-             let te = NCicTypeChecker.debruijn uri len [] te in
+             let te = NCicTypeChecker.debruijn uri len [] ~subst te in
              let metasenv, subst, te, _ = check_type metasenv subst tys te in
              let context,te = NCicReduction.split_prods ~subst tys leftno te in
              let _,chopped_context_rev =
@@ -685,7 +795,7 @@ prerr_endline ("===============\n" ^ NCicPp.ppobj (uri,height,metasenv,subst,obj
                       "and those of its inductive type"))))
                    else
                     metasenv,subst,item1::context
-                ) (metasenv,subst,[]) sx_context_ty_rev sx_context_te_rev
+                ) (metasenv,subst,tys) sx_context_ty_rev sx_context_te_rev
               with Invalid_argument "List.fold_left2" -> assert false in
              let con_sort= NCicTypeChecker.typeof ~subst ~metasenv context te in
               (match
@@ -717,7 +827,8 @@ prerr_endline ("===============\n" ^ NCicPp.ppobj (uri,height,metasenv,subst,obj
                 raise
                   (RefineFailure
                     (lazy (localise te,
-                      "Non positive occurence in " ^ NUri.string_of_uri uri)))
+                      "Non positive occurence in " ^
+                        NCicPp.ppterm ~metasenv ~subst ~context te)))
               else
                let relsno = List.length itl + leftno in
                let te =