+module C = Cic
+module I = CicInspect
+module S = CicSubstitution
+module TC = CicTypeChecker
+module P = PrimitiveTactics
+module T = Tacticals
+module PESR = ProofEngineStructuralRules
+module F = FreshNamesGenerator
+module PET = ProofEngineTypes
+module RT = ReductionTactics
+module E = CicEnvironment
+module R = CicReduction
+module Un = CicUniv
+module PEH = ProofEngineHelpers
+
+let premise_pattern what = None, [what, C.Implicit (Some `Hole)], None
+
+let get_inductive_def uri =
+ match E.get_obj Un.oblivion_ugraph uri with
+ | C.InductiveDefinition (tys, _, lpsno, _), _ ->
+ lpsno, tys
+ | _ -> assert false
+
+let is_not_recursive uri tyno tys =
+ let map mutinds (_, ty) =
+(* FG: we can do much better here *)
+ let map mutinds (_, t) = I.S.union mutinds (I.get_mutinds_of_uri uri t) in
+(**********************************)
+ let premises, _ = PEH.split_with_whd ([], ty) in
+ List.fold_left map mutinds (List.tl premises)
+ in
+ let msg = "recursiveness check non implemented for mutually inductive types" in
+ if List.length tys > 1 then raise (PET.Fail (lazy msg)) else
+ let _, _, _, constructors = List.nth tys tyno in
+ let mutinds = List.fold_left map I.S.empty constructors in
+ I.S.is_empty mutinds
+
+let rec check_type sorts metasenv context t =
+ match R.whd ~delta:true context t with
+ | C.MutInd (uri, tyno, _) as t ->
+ let lpsno, tys = get_inductive_def uri in
+ let _, inductive, arity, _ = List.nth tys tyno in
+ let _, psno = PEH.split_with_whd ([], arity) in
+ let not_relation = (lpsno = psno) in
+ let not_recursive = is_not_recursive uri tyno tys in
+ let ty_ty, _ = TC.type_of_aux' metasenv context t Un.oblivion_ugraph in
+ let sort = match PEH.split_with_whd (context, ty_ty) with
+ | (_, C.Sort sort) ::_ , _ -> CicPp.ppsort sort
+ | (_, C.Meta _) :: _, _ -> CicPp.ppsort (C.Type (Un.fresh ()))
+ | _ -> assert false
+ in
+ let right_sort = List.mem sort sorts in
+ if not_relation && inductive && not_recursive && right_sort then
+ begin
+ HLog.warn (Printf.sprintf "Decomposing %s %u" (UriManager.string_of_uri uri) (succ tyno));
+ true
+ end
+ else false
+ | C.Appl (hd :: tl) -> check_type sorts metasenv context hd
+ | _ -> false