Reporting cleanup 16: UnknownNode -> no node key

Summary: No dummy node key, as a consequence the option `--skip-duplicated-types` will have no effect on issues with no node key, i.e. issues reported by non-biabduction non-eradicate checkers.

Reviewed By: martinoluca

Differential Revision: D9633564

fbshipit-source-id: 9ff8abf21

infer/src/IR/Errlog.ml

@@ -266,7 +266,7 @@ let log_issue procname ~clang_method_kind severity err_log ~loc ~node ~session ~
       let node_id, node_key =
         match node with
         | UnknownNode ->
-            (0, Some Procdesc.NodeKey.dummy)
+            (0, None)
         | FrontendNode {node_key} ->
             (0, Some node_key)
         | BackendNode {node} ->

infer/src/IR/Procdesc.ml

@@ -24,8 +24,6 @@ module NodeKey = struct
 
 
   let of_frontend_node_key = Utils.better_hash
-
-  let dummy = Utils.better_hash "DUMMY"
 end
 
 (* =============== START of module Node =============== *)

infer/src/IR/Procdesc.mli

@@ -11,8 +11,6 @@ open! IStd
 module NodeKey : sig
   type t
 
-  val dummy : t
-
   val to_string : t -> string
 
   val of_frontend_node_key : string -> t