X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Focaml%2Fcic_proof_checking%2FcicElim.ml;h=c668d1c9be33420a1b9222a8646c8c3408b7a436;hb=4167cea65ca58897d1a3dbb81ff95de5074700cc;hp=fb568613c943c8b3b7389d9d09d039d8e88b8046;hpb=a93a94942ad58d8645af1fd94bef8fa31d9541a4;p=helm.git

diff --git a/helm/ocaml/cic_proof_checking/cicElim.ml b/helm/ocaml/cic_proof_checking/cicElim.ml
index fb568613c..c668d1c9b 100644
--- a/helm/ocaml/cic_proof_checking/cicElim.ml
+++ b/helm/ocaml/cic_proof_checking/cicElim.ml
@@ -25,7 +25,7 @@
 
 open Printf
 
-exception Elim_failure of string
+exception Elim_failure of string Lazy.t
 exception Can_t_eliminate
 
 let debug_print = fun _ -> ()
@@ -255,7 +255,7 @@ let branch (uri, typeno) insource liftno paramsno t fix head args =
   let t = strip_left_params liftno paramsno t in
   branch (uri, typeno) insource paramsno t fix head args
 
-let elim_of ?(sort = Cic.Type (CicUniv.fresh ())) uri typeno =
+let elim_of ~sort uri typeno =
   counter := ~-1;
   let (obj, univ) = (CicEnvironment.get_obj CicUniv.empty_ugraph uri) in
   match obj with
@@ -268,10 +268,14 @@ let elim_of ?(sort = Cic.Type (CicUniv.fresh ())) uri typeno =
       let paramsno = count_pi ty in (* number of (left or right) parameters *)
       let rightno = paramsno - leftno in
       let dependent = (strip_pi ty <> Cic.Sort Cic.Prop) in
+let head = match strip_pi ty with Cic.Sort s -> s in
       let conslen = List.length constructors in
       let consno = ref (conslen + 1) in
-      if (not dependent) && (sort <> Cic.Prop) && (conslen > 1) then
-        raise Can_t_eliminate;
+      if
+       not
+        (CicTypeChecker.check_allowed_sort_elimination uri typeno head sort)
+      then
+       raise Can_t_eliminate;
       let indty =
         let indty = Cic.MutInd (uri, typeno, []) in
         if paramsno = 0 then
@@ -382,9 +386,9 @@ debug_print (lazy (CicPp.ppterm eliminator_body));
         try
           CicTypeChecker.type_of_aux' [] [] eliminator_body CicUniv.empty_ugraph
         with CicTypeChecker.TypeCheckerFailure msg ->
-          raise (Elim_failure (sprintf 
+          raise (Elim_failure (lazy (sprintf 
             "type checker failure while type checking:\n%s\nerror:\n%s"
-            (CicPp.ppterm eliminator_body) msg))
+            (CicPp.ppterm eliminator_body) (Lazy.force msg))))
       in
       if not (fst (CicReduction.are_convertible []
         eliminator_type computed_type ugraph))