X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fcic_unification%2FcoercGraph.ml;h=61df4ceb5548e22a263039e48edc0024b7bc5064;hb=d17a38ddca548c784e9efa7c55e87c80203b024d;hp=17301e4d6bb4cbb81ef8498a3ccf69e6daf37c93;hpb=e79fd328fe626dbd8c76183c36f721119e9fb668;p=helm.git

diff --git a/helm/software/components/cic_unification/coercGraph.ml b/helm/software/components/cic_unification/coercGraph.ml
index 17301e4d6..61df4ceb5 100644
--- a/helm/software/components/cic_unification/coercGraph.ml
+++ b/helm/software/components/cic_unification/coercGraph.ml
@@ -304,10 +304,16 @@ let lb (c,_,_) =
 
 (* given the set { (s,u1,u2) | u1:s->t1 /\ u2:s->t2 } removes the elements 
  * (s,_,_) such that (s',_,_) is in the set and there exists a coercion s->s' *)
-let rec min acc = function
+let rec min acc skipped = function
   | c::tl -> 
-    if List.exists (lb c) (tl@acc) then min acc tl else min (c::acc) tl
-  | [] -> acc
+    if List.exists (lb c) (tl@acc) 
+    then min acc (c::skipped) tl else min (c::acc) skipped tl
+  | [] -> acc, skipped
+;;
+
+
+let sort l = 
+  let low, high = min [] [] l in low @ high
 ;;
 
 let meets metasenv subst context (grow_left,left) (grow_right,right) =
@@ -321,12 +327,12 @@ let meets metasenv subst context (grow_left,left) (grow_right,right) =
   in
   List.map 
     (fun (c,uo1,uo2) -> 
-      let metasenv, uo1 = 
-        if grow_left then saturate metasenv uo1 else metasenv, None in
-      let metasenv, uo2 = 
-        if grow_right then saturate metasenv uo2 else metasenv, None in
+      let metasenv, uo1 = saturate metasenv uo1 in
+      let metasenv, uo2 = saturate metasenv uo2 in
       c,metasenv, uo1, uo2)
-    (min [] (intersect (grow left) (grow right)))
+    (sort (intersect 
+      (if grow_left then grow left else [left,None]) 
+      (if grow_right then grow right else [right,None])))
 ;;
 
 (* EOF *)