Warn about the unavailability of nier due to errors.

lib/onnx/onnx.ml

@@ -119,7 +119,7 @@ let produce_cfg (g : Oproto.Onnx.GraphProto.t) =
         | "MaxPool" -> NCFG.Node.MaxPool
         | "Conv" -> NCFG.Node.Conv
         | "Identity" -> NCFG.Node.Identity
-        | _ -> raise (ParseError ("Unsupported ONNX operator: " ^ o)))
+        | _ -> raise (ParseError ("Unsupported ONNX operator " ^ o)))
     in
     List.fold ~f:(fun acc n -> get_node_operator_cfg n :: acc) ~init:[] ns
   in

src/language.ml

@@ -95,7 +95,14 @@ let onnx_parser env _ filename _ =
   match model with
   | Error s -> Loc.errorm "%s" s
   | Ok { n_inputs; n_outputs; nier } ->
-    let nier = Result.ok nier (* TODO: Warn about parsing errors? *) in
+    let nier =
+      match nier with
+      | Error msg ->
+        Logs.warn (fun m ->
+          m "Cannot build network intermediate representation:@ %s" msg);
+        None
+      | Ok nier -> Some nier
+    in
     register_nn_as_tuple n_inputs n_outputs filename nier env
 
 let ovo_parser env _ filename _ =