We no longer apply the subst to a Meta in force_does_not_occur. In this

[helm.git] / helm / ocaml / cic_unification / cicMetaSubst.ml

diff --git a/helm/ocaml/cic_unification/cicMetaSubst.ml b/helm/ocaml/cic_unification/cicMetaSubst.ml
index da9cdb0ac2e7902da622ec818c03f705747bc3d1..637c346b06972b7dcc747ff4298414c2824e2899 100644 (file)
--- a/helm/ocaml/cic_unification/cicMetaSubst.ml
+++ b/helm/ocaml/cic_unification/cicMetaSubst.ml
@@ -51,24 +51,23 @@ let rec force_does_not_occur subst to_be_restricted t =
     | C.Sort _ as t -> t
     | C.Implicit -> assert false
     | C.Meta (n, l) ->
-        (try
-          aux k (CicSubstitution.lift_meta l (List.assoc n subst))
-        with Not_found ->
-          let l' =
-            let i = ref 0 in
-            List.map
-              (function
-                | None -> None
-                | Some t ->
-                    incr i;
-                    try
-                      Some (aux k t)
-                    with Occur ->
-                      more_to_be_restricted := (n,!i) :: !more_to_be_restricted;
-                      None)
-              l
-          in
-          C.Meta (n, l'))
+       (* we do not retrieve the term associated to ?n in subst since *)
+       (* in this way we can restrict if something goes wrong         *)
+       let l' =
+         let i = ref 0 in
+         List.map
+           (function
+             | None -> None
+             | Some t ->
+                 incr i;
+                 try
+                   Some (aux k t)
+                 with Occur ->
+                   more_to_be_restricted := (n,!i) :: !more_to_be_restricted;
+                   None)
+           l
+       in
+        C.Meta (n, l')
     | C.Cast (te,ty) -> C.Cast (aux k te, aux k ty)
     | C.Prod (name,so,dest) -> C.Prod (name, aux k so, aux (k+1) dest)
     | C.Lambda (name,so,dest) -> C.Lambda (name, aux k so, aux (k+1) dest)
@@ -259,24 +258,23 @@ let delift n subst context metasenv l t =
             "Cannot unify the metavariable ?%d with a term that has as subterm %s in which the same metavariable occurs (occur check)"
             i (CicPp.ppterm t)))
         else
-          (try
-            deliftaux k (S.lift_meta l (List.assoc i subst))
-          with Not_found ->
-            let rec deliftl j =
-             function
-                [] -> []
-              | None::tl -> None::(deliftl (j+1) tl)
-              | (Some t)::tl ->
-                 let l1' = (deliftl (j+1) tl) in
-                  try
-                   Some (deliftaux k t)::l1'
-                  with
-                     NotInTheList
-                   | MetaSubstFailure _ ->
-                      to_be_restricted := (i,j)::!to_be_restricted ; None::l1'
-            in
-             let l' = deliftl 1 l1 in
-              C.Meta(i,l'))
+         (* I do not consider the term associated to ?i in subst since *)
+         (* in this way I can restrict if something goes wrong.        *)
+          let rec deliftl j =
+           function
+              [] -> []
+            | None::tl -> None::(deliftl (j+1) tl)
+            | (Some t)::tl ->
+               let l1' = (deliftl (j+1) tl) in
+                try
+                 Some (deliftaux k t)::l1'
+                with
+                   NotInTheList
+                 | MetaSubstFailure _ ->
+                    to_be_restricted := (i,j)::!to_be_restricted ; None::l1'
+          in
+           let l' = deliftl 1 l1 in
+            C.Meta(i,l')
      | C.Sort _ as t -> t
      | C.Implicit as t -> t
      | C.Cast (te,ty) -> C.Cast (deliftaux k te, deliftaux k ty)