X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=components%2Fcic_unification%2FcicUnification.ml;h=ecde4cdfd9bd2fb1dee201d64f96c75f8437a9ce;hb=2499f5fdcf4dbfecc6f4fafe925b24ae76f14be8;hp=44712199e412b370170b8753c6aa0e488d6a12bf;hpb=b934a94a5d005f9d8e668ef49ec83487090a787b;p=helm.git

diff --git a/components/cic_unification/cicUnification.ml b/components/cic_unification/cicUnification.ml
index 44712199e..ecde4cdfd 100644
--- a/components/cic_unification/cicUnification.ml
+++ b/components/cic_unification/cicUnification.ml
@@ -578,13 +578,14 @@ debug_print (lazy ("restringo Meta n." ^ (string_of_int n) ^ "on variable n." ^
                 fo_unif_l 
                   test_equality_only subst metasenv (lr1, lr2)  ugraph
               with 
-              | UnificationFailure _
-              | Uncertain _ as exn -> 
+              | UnificationFailure s
+              | Uncertain s as exn -> 
                   (match l1, l2 with
                   | (((Cic.Const (uri1, ens1)) as c1) :: tl1), 
                      (((Cic.Const (uri2, ens2)) as c2) :: tl2) when
                     CoercGraph.is_a_coercion c1 && 
-                    CoercGraph.is_a_coercion c2 ->
+                    CoercGraph.is_a_coercion c2 &&
+                    not (UriManager.eq uri1 uri2) ->
                       let body1, attrs1, ugraph = 
                         match CicEnvironment.get_obj ugraph uri1 with
                         | Cic.Constant (_,Some bo, _, _, attrs),u  -> bo,attrs,u
@@ -596,9 +597,15 @@ debug_print (lazy ("restringo Meta n." ^ (string_of_int n) ^ "on variable n." ^
                         | _ -> assert false
                       in
                       let is_composite1 = 
-                        List.exists ((=) (`Class `Coercion)) attrs1 in
+                        List.exists 
+                         (function `Class (`Coercion _) -> true | _-> false) 
+                         attrs1 
+                      in
                       let is_composite2 = 
-                        List.exists ((=) (`Class `Coercion)) attrs2 in
+                        List.exists 
+                         (function `Class (`Coercion _) -> true | _-> false) 
+                         attrs2 
+                      in
                       (match is_composite1, is_composite2 with
                       | false, false -> raise exn
                       | true, false ->