+and check_allowed_sort_elimination ~subst ~metasenv r =
+ let mkapp he arg =
+ match he with
+ | C.Appl l -> C.Appl (l @ [arg])
+ | t -> C.Appl [t;arg] in
+ let rec aux context ind arity1 arity2 =
+ let arity1 = R.whd ~subst context arity1 in
+ let arity2 = R.whd ~subst context arity2 in
+ match arity1,arity2 with
+ | C.Prod (name,so1,de1), C.Prod (_,so2,de2) ->
+ if not (R.are_convertible ~metasenv ~subst context so1 so2) then
+ raise (TypeCheckerFailure (lazy (Printf.sprintf
+ "In outtype: expected %s, found %s"
+ (PP.ppterm ~subst ~metasenv ~context so1)
+ (PP.ppterm ~subst ~metasenv ~context so2)
+ )));
+ aux ((name, C.Decl so1)::context)
+ (mkapp (S.lift 1 ind) (C.Rel 1)) de1 de2
+ | C.Sort _, C.Prod (name,so,ta) ->
+ if not (R.are_convertible ~metasenv ~subst context so ind) then
+ raise (TypeCheckerFailure (lazy (Printf.sprintf
+ "In outtype: expected %s, found %s"
+ (PP.ppterm ~subst ~metasenv ~context ind)
+ (PP.ppterm ~subst ~metasenv ~context so)
+ )));
+ (match arity1, R.whd ~subst ((name,C.Decl so)::context) ta with
+ | (C.Sort C.Type _, C.Sort _)
+ | (C.Sort C.Prop, C.Sort C.Prop) -> ()
+ | (C.Sort C.Prop, C.Sort C.Type _) ->
+ (* TODO: we should pass all these parameters since we
+ * have them already *)
+ let _,leftno,itl,_,i = E.get_checked_indtys r in
+ let itl_len = List.length itl in
+ let _,itname,ittype,cl = List.nth itl i in
+ let cl_len = List.length cl in
+ (* is it a singleton, non recursive and non informative
+ definition or an empty one? *)
+ if not
+ (cl_len = 0 ||
+ (itl_len = 1 && cl_len = 1 &&
+ let _,_,constrty = List.hd cl in
+ is_non_recursive_singleton
+ ~subst r itname ittype constrty &&
+ is_non_informative ~metasenv ~subst leftno constrty))
+ then
+ raise (TypeCheckerFailure (lazy
+ ("Sort elimination not allowed")));
+ | _,_ -> ())
+ | _,_ -> ()
+ in
+ aux
+