[nullsafe] Remove custom hash calculation for err_instance

Summary:
At some point, there was a custom equality function that deliberately ignored some fields in err_instance. It was deleted in D4232422, so having a custom hash function does not serve any purpose anymore.

Since 2016 there was no known problems with the change in D4232422.

If we decide that we need similar behavior that was before D4232422, it will be easier to reimplement the functionality again.

Reviewed By: jberdine

Differential Revision: D17313660

fbshipit-source-id: 5c6c29a0b

infer/src/nullsafe/typeErr.ml

@@ -93,41 +93,7 @@ module H = Hashtbl.Make (struct
 
   let equal = [%compare.equal: t]
 
-  let err_instance_hash x =
-    let string_hash s = Hashtbl.hash s in
-    let string_opt_hash so = Hashtbl.hash so in
-    match x with
-    | Condition_redundant (b, so, nn) ->
-        Hashtbl.hash (1, b, string_opt_hash so, nn)
-    | Field_not_initialized (fn, pn) ->
-        Hashtbl.hash (2, string_hash (Typ.Fieldname.to_string fn ^ Typ.Procname.to_string pn))
-    | Field_annotation_inconsistent (fn, _) ->
-        Hashtbl.hash (3, string_hash (Typ.Fieldname.to_string fn))
-    | Field_over_annotated (fn, pn) ->
-        Hashtbl.hash (4, string_hash (Typ.Fieldname.to_string fn ^ Typ.Procname.to_string pn))
-    | Null_field_access (so, fn, _, _) ->
-        Hashtbl.hash (5, string_opt_hash so, string_hash (Typ.Fieldname.to_string fn))
-    | Call_receiver_annotation_inconsistent (so, pn, _) ->
-        Hashtbl.hash (6, string_opt_hash so, Typ.Procname.hash pn)
-    | Parameter_annotation_inconsistent (s, n, pn, _, _) ->
-        Hashtbl.hash (7, string_hash s, n, Typ.Procname.hash pn)
-    | Return_annotation_inconsistent (pn, _) ->
-        Hashtbl.hash (8, Typ.Procname.hash pn)
-    | Return_over_annotated pn ->
-        Hashtbl.hash (9, Typ.Procname.hash pn)
-    | Inconsistent_subclass_return_annotation (pn, opn) ->
-        Hashtbl.hash (10, Typ.Procname.hash pn, Typ.Procname.hash opn)
-    | Inconsistent_subclass_parameter_annotation (param_name, pos, pn, opn) ->
-        let pn_hash = string_hash param_name in
-        Hashtbl.hash (11, pn_hash, pos, Typ.Procname.hash pn, Typ.Procname.hash opn)
-
-
-  let hash (err_inst, instr_ref_opt) =
-    let x =
-      match instr_ref_opt with None -> None | Some instr_ref -> Some (InstrRef.hash instr_ref)
-    in
-    let y = err_instance_hash err_inst in
-    Hashtbl.hash (x, y)
+  let hash = Hashtbl.hash
 end
 (* H *))