+*)
+ begin
+ let subst,metasenv,ugraph1 =
+ let (_,_,meta_type) = CicUtil.lookup_meta n metasenv in
+ (try
+ let tyt,ugraph1 =
+ type_of_aux' metasenv subst context t ugraph
+ in
+ fo_unif_subst
+ test_equality_only
+ subst context metasenv tyt (S.lift_meta l meta_type) ugraph1
+ with
+ UnificationFailure msg
+ | Uncertain msg ->
+ prerr_endline msg;raise (UnificationFailure msg)
+ | AssertFailure _ ->
+ prerr_endline "siamo allo huge hack";
+ (* TODO huge hack!!!!
+ * we keep on unifying/refining in the hope that
+ * the problem will be eventually solved.
+ * In the meantime we're breaking a big invariant:
+ * the terms that we are unifying are no longer well
+ * typed in the current context (in the worst case
+ * we could even diverge) *)
+ (subst, metasenv,ugraph)) in
+ let t',metasenv,subst =
+ try
+ CicMetaSubst.delift n subst context metasenv l t
+ with
+ (CicMetaSubst.MetaSubstFailure msg)->
+ raise (UnificationFailure msg)
+ | (CicMetaSubst.Uncertain msg) -> raise (Uncertain msg)
+ in
+ let t'',ugraph2 =
+ match t' with
+ C.Sort (C.Type u) when not test_equality_only ->
+ let u' = CicUniv.fresh () in
+ let s = C.Sort (C.Type u') in
+ let ugraph2 =
+ CicUniv.add_ge (upper u u') (lower u u') ugraph1
+ in
+ s,ugraph2
+ | _ -> t',ugraph1
+ in
+ (* Unifying the types may have already instantiated n. Let's check *)
+ try
+ let (_, oldt,_) = CicUtil.lookup_subst n subst in
+ let lifted_oldt = S.lift_meta l oldt in
+ fo_unif_subst_ordered
+ test_equality_only subst context metasenv t lifted_oldt ugraph2
+ with
+ CicUtil.Subst_not_found _ ->
+ let (_, context, ty) = CicUtil.lookup_meta n metasenv in
+ let subst = (n, (context, t'',ty)) :: subst in
+ let metasenv =
+ List.filter (fun (m,_,_) -> not (n = m)) metasenv in
+ subst, metasenv, ugraph2
+ end
+