X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fcic_unification%2FcoercGraph.ml;h=2fa2c4b0c5ca4ba216534de62d26cbebb9e02bcd;hb=5e5d161f094982275ce39dbb4780c106e4475b37;hp=637944e6b8401e4df87c38e793c40a740d68da65;hpb=910c252965fe17d6b5af92e4658e7d02bac82d58;p=helm.git

diff --git a/helm/software/components/cic_unification/coercGraph.ml b/helm/software/components/cic_unification/coercGraph.ml
index 637944e6b..2fa2c4b0c 100644
--- a/helm/software/components/cic_unification/coercGraph.ml
+++ b/helm/software/components/cic_unification/coercGraph.ml
@@ -70,7 +70,7 @@ let saturate_coercion ul metasenv subst context =
 ;;
           
 (* searches a coercion fron src to tgt in the !coercions list *)
-let look_for_coercion' metasenv subst context src tgt =
+let look_for_coercion_carr metasenv subst context src tgt =
   let is_dead = function CoercDb.Dead -> true | _ -> false in
   let pp_l s l =
    match l with
@@ -108,10 +108,18 @@ let look_for_coercion' metasenv subst context src tgt =
      | ul -> SomeCoercion (saturate_coercion ul metasenv subst context))
 ;;
 
+let rec count_pi c s t =
+  match CicReduction.whd ~delta:false ~subst:s c t with
+  | Cic.Prod (_,_,t) -> 1 + count_pi c s t
+  | _ -> 0
+;;
+
 let look_for_coercion metasenv subst context src tgt = 
-  let src_uri = CoercDb.coerc_carr_of_term src 0 in
-  let tgt_uri = CoercDb.coerc_carr_of_term tgt 0 in
-  look_for_coercion' metasenv subst context src_uri tgt_uri
+  let src_arity = count_pi context subst src in
+  let tgt_arity = count_pi context subst tgt in
+  let src_carr = CoercDb.coerc_carr_of_term src src_arity in
+  let tgt_carr = CoercDb.coerc_carr_of_term tgt tgt_arity in
+  look_for_coercion_carr metasenv subst context src_carr tgt_carr
 
 let source_of t = 
   match CoercDb.is_a_coercion t with