X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Facic_procedural%2FproceduralOptimizer.ml;h=2faade402402068c51a1137976cd2c91facd5dd9;hb=9e7df95a820cb91d075f1a20d703175da874596c;hp=a397de41e8fa3b8b82b930968a1ef1251d45baec;hpb=1b70a1f66be53f76e475383e86d63c2b5c1fbcaa;p=helm.git

diff --git a/helm/software/components/acic_procedural/proceduralOptimizer.ml b/helm/software/components/acic_procedural/proceduralOptimizer.ml
index a397de41e..2faade402 100644
--- a/helm/software/components/acic_procedural/proceduralOptimizer.ml
+++ b/helm/software/components/acic_procedural/proceduralOptimizer.ml
@@ -42,7 +42,7 @@ module Cl   = ProceduralClassify
 
 (* debugging ****************************************************************)
 
-let debug = ref false
+let debug = ref true
 
 (* term optimization ********************************************************)
 
@@ -192,6 +192,10 @@ and opt_mutcase_critical g st es c uri tyno outty arg cases =
       opt_mutcase_plain g st es c uri tyno outty arg cases
    else
    let predicate = clear_absts rpsno (1 - sort_disp) outty in   
+   if H.occurs c ~what:(C.Rel 0) ~where:predicate then
+(* FG: the transformation is not possible, we fall back into the plain case *)
+      opt_mutcase_plain g st es c uri tyno outty arg cases
+   else
    let is_recursive t =
       I.S.mem tyno (I.get_mutinds_of_uri uri t) 
    in
@@ -211,8 +215,13 @@ and opt_mutcase_critical g st es c uri tyno outty arg cases =
    in
    let lifted_cases = List.map2 map2 cases constructors in
    let args = eliminator :: lps @ predicate :: lifted_cases @ rps @ [arg] in
-   let x = H.refine c (C.Appl args) in
-   opt_proof g (info st "Optimizer: remove 3") es c x
+   try 
+      let x = H.refine c (C.Appl args) in
+      opt_proof g (info st "Optimizer: remove 3") es c x	 
+   with e ->
+(* FG: the transformation is not possible, we fall back into the plain case *)
+      let st = info st ("Optimizer: refine_error: " ^ Printexc.to_string e) in
+      opt_mutcase_plain g st es c uri tyno outty arg cases
 
 and opt_mutcase_plain g st es c uri tyno outty arg cases =
    let g st v =