+ subst,metasenv,ugraph,context_terms, ty_terms
+
+(* saturate_term newmeta metasenv context ty *)
+(* Given a type [ty] (a backbone), it returns its head and a new metasenv in *)
+(* which there is new a META for each hypothesis, a list of arguments for the *)
+(* new applications and the index of the last new META introduced. The nth *)
+(* argument in the list of arguments is just the nth new META. *)
+let saturate_term newmeta metasenv context ty =
+ let module C = Cic in
+ let module S = CicSubstitution in
+ let rec aux newmeta ty =
+ let ty' = ty in
+ match ty' with
+ C.Cast (he,_) -> aux newmeta he
+(* CSC: patch to generate ?1 : ?2 : Type in place of ?1 : Type to simulate ?1 :< Type
+ (* If the expected type is a Type, then also Set is OK ==>
+ * we accept any term of type Type *)
+ (*CSC: BUG HERE: in this way it is possible for the term of
+ * type Type to be different from a Sort!!! *)
+ | C.Prod (name,(C.Sort (C.Type _) as s),t) ->
+ (* TASSI: ask CSC if BUG HERE refers to the C.Cast or C.Propd case *)
+ let irl =
+ CicMkImplicit.identity_relocation_list_for_metavariable context
+ in
+ let newargument = C.Meta (newmeta+1,irl) in
+ let (res,newmetasenv,arguments,lastmeta) =
+ aux (newmeta + 2) (S.subst newargument t)
+ in
+ res,
+ (newmeta,[],s)::(newmeta+1,context,C.Meta (newmeta,[]))::newmetasenv,
+ newargument::arguments,lastmeta
+*)
+ | C.Prod (name,s,t) ->
+ let irl =
+ CicMkImplicit.identity_relocation_list_for_metavariable context
+ in
+ let newargument = C.Meta (newmeta,irl) in
+ let (res,newmetasenv,arguments,lastmeta) =
+ aux (newmeta + 1) (S.subst newargument t)
+ in
+ let s' = CicReduction.normalize ~delta:false context s in
+ res,(newmeta,context,s')::newmetasenv,newargument::arguments,lastmeta
+ (** NORMALIZE RATIONALE
+ * we normalize the target only NOW since we may be in this case:
+ * A1 -> A2 -> T where T = (\lambda x.A3 -> P) k
+ * and we want a mesasenv with ?1:A1 and ?2:A2 and not
+ * ?1, ?2, ?3 (that is the one we whould get if we start from the
+ * beta-normalized A1 -> A2 -> A3 -> P **)
+ | t -> (CicReduction.normalize ~delta:false context t),[],[],newmeta
+ in
+ (* WARNING: here we are using the invariant that above the most *)
+ (* recente new_meta() there are no used metas. *)
+ let (res,newmetasenv,arguments,lastmeta) = aux newmeta ty in
+ res,metasenv @ newmetasenv,arguments,lastmeta
+