diff --git a/infer/src/IR/Errlog.ml b/infer/src/IR/Errlog.ml
index 881850e8e..a0898ac4f 100644
--- a/infer/src/IR/Errlog.ml
+++ b/infer/src/IR/Errlog.ml
@@ -60,7 +60,9 @@ let compute_local_exception_line loc_trace =
   List.fold_until ~init:(None, None) ~f:compute_local_exception_line ~finish:snd loc_trace
 
 
-type node_id_key = {node_id: int; node_key: Procdesc.NodeKey.t}
+type node_id_key =
+  | FrontendNode of {node_key: Procdesc.NodeKey.t}
+  | BackendNode of {node_id: Procdesc.Node.id; node_key: Procdesc.NodeKey.t}
 
 type err_key =
   { severity: Exceptions.severity
@@ -171,8 +173,15 @@ let pp_warnings fmt (errlog: t) =
 let pp_html source path_to_root fmt (errlog: t) =
   let pp_eds fmt err_datas =
     let pp_nodeid_session_loc fmt err_data =
+      let node_id =
+        match err_data.node_id_key with
+        | FrontendNode _ ->
+            0
+        | BackendNode {node_id} ->
+            (node_id :> int)
+      in
       Io_infer.Html.pp_session_link source path_to_root fmt
-        (err_data.node_id_key.node_id, err_data.session, err_data.loc.Location.line)
+        (node_id, err_data.session, err_data.loc.Location.line)
     in
     ErrDataSet.iter (pp_nodeid_session_loc fmt) err_datas
   in
diff --git a/infer/src/IR/Errlog.mli b/infer/src/IR/Errlog.mli
index 9ecc02936..b83080564 100644
--- a/infer/src/IR/Errlog.mli
+++ b/infer/src/IR/Errlog.mli
@@ -34,7 +34,9 @@ val compute_local_exception_line : loc_trace -> int option
     This extra information adds value to the report itself, and may avoid
     digging into the trace to understand the cause of the report. *)
 
-type node_id_key = {node_id: int; node_key: Procdesc.NodeKey.t}
+type node_id_key =
+  | FrontendNode of {node_key: Procdesc.NodeKey.t}
+  | BackendNode of {node_id: Procdesc.Node.id; node_key: Procdesc.NodeKey.t}
 
 type err_key = private
   { severity: Exceptions.severity
diff --git a/infer/src/backend/InferPrint.ml b/infer/src/backend/InferPrint.ml
index 4d99c8e1a..112cab1ea 100644
--- a/infer/src/backend/InferPrint.ml
+++ b/infer/src/backend/InferPrint.ml
@@ -301,6 +301,11 @@ module JsonIssuePrinter = MakeJsonListPrinter (struct
         | _ ->
             Typ.Procname.to_string proc_name
       in
+      let node_key =
+        match err_data.node_id_key with
+        | FrontendNode {node_key} | BackendNode {node_key} ->
+            Procdesc.NodeKey.to_string node_key
+      in
       let bug =
         { Jsonbug_j.bug_class= Exceptions.err_class_string err_data.err_class
         ; kind= severity
@@ -315,7 +320,7 @@ module JsonIssuePrinter = MakeJsonListPrinter (struct
         ; procedure_start_line
         ; file
         ; bug_trace= loc_trace_to_jsonbug_record err_data.loc_trace err_key.severity
-        ; node_key= err_data.node_id_key.node_key |> Procdesc.NodeKey.to_string
+        ; node_key
         ; key= compute_key bug_type proc_name file
         ; hash= compute_hash severity bug_type proc_name file qualifier
         ; dotty= error_desc_to_dotty_string err_key.err_desc
diff --git a/infer/src/backend/reporting.ml b/infer/src/backend/reporting.ml
index 17064b131..317f303a9 100644
--- a/infer/src/backend/reporting.ml
+++ b/infer/src/backend/reporting.ml
@@ -22,7 +22,7 @@ let log_issue_from_errlog procname ~clang_method_kind severity err_log ~loc ~nod
 
 
 let log_frontend_issue procname severity errlog ~loc ~node_key ~ltr ~linters_def_file ~doc_url exn =
-  let node_id_key = {Errlog.node_id= 0; node_key} in
+  let node_id_key = Errlog.FrontendNode {node_key} in
   log_issue_from_errlog procname ~clang_method_kind:None severity errlog ~loc ~node_id_key ~ltr
     ~linters_def_file ~doc_url ~access:None ~extras:None exn
 
diff --git a/infer/src/biabduction/State.ml b/infer/src/biabduction/State.ml
index 720e3af80..c5c35aea6 100644
--- a/infer/src/biabduction/State.ml
+++ b/infer/src/biabduction/State.ml
@@ -165,8 +165,8 @@ let mk_find_duplicate_nodes : Procdesc.t -> Procdesc.Node.t -> Procdesc.NodeSet.
 let get_node_id () = Procdesc.Node.get_id !gs.last_node
 
 let get_node_id_key () =
-  { Errlog.node_id= (Procdesc.Node.get_id !gs.last_node :> int)
-  ; node_key= Procdesc.Node.compute_key !gs.last_node }
+  Errlog.BackendNode
+    {node_id= Procdesc.Node.get_id !gs.last_node; node_key= Procdesc.Node.compute_key !gs.last_node}
 
 
 let get_inst_update pos =