fold_slope_range, java_get_vararg_values: got rid of refs

Reviewed By: ngorogiannis

Differential Revision: D8026721

fbshipit-source-id: 9564a19

infer/src/IR/Procdesc.ml

@@ -306,19 +306,18 @@ let fold_instrs pdesc ~init ~f =
   fold_nodes ~f:fold_node ~init pdesc
 
 
-(** iterate between two nodes or until we reach a branching structure *)
-let iter_slope_range f src_node dst_node =
-  let visited = ref NodeSet.empty in
-  let rec do_node node =
-    visited := NodeSet.add node !visited ;
-    f node ;
+(** fold between two nodes or until we reach a branching structure *)
+let fold_slope_range =
+  let rec aux node visited acc ~f =
+    let visited = NodeSet.add node visited in
+    let acc = f acc node in
     match Node.get_succs node with
-    | [n] ->
-        if not (NodeSet.mem n !visited) && not (Node.equal node dst_node) then do_node n
+    | [n] when not (NodeSet.mem n visited) ->
+        aux n visited acc ~f
     | _ ->
-        ()
+        acc
   in
-  do_node src_node
+  fun src_node dst_node ~init ~f -> aux src_node (NodeSet.singleton dst_node) init ~f
 
 
 (** Set the exit node of the proc desc *)

infer/src/IR/Procdesc.mli

@@ -187,8 +187,8 @@ val iter_instrs : (Node.t -> Sil.instr -> unit) -> t -> unit
 val iter_nodes : (Node.t -> unit) -> t -> unit
 (** iterate over all the nodes of a procedure *)
 
-val iter_slope_range : (Node.t -> unit) -> Node.t -> Node.t -> unit
-(** iterate between two nodes or until we reach a branching structure *)
+val fold_slope_range : Node.t -> Node.t -> init:'accum -> f:('accum -> Node.t -> 'accum) -> 'accum
+(** fold between two nodes or until we reach a branching structure *)
 
 val set_succs_exn_only : Node.t -> Node.t list -> unit
 

infer/src/absint/PatternMatch.ml

@@ -236,24 +236,22 @@ let method_is_initializer (tenv: Tenv.t) (proc_attributes: ProcAttributes.t) : b
 
 (** Get the vararg values by looking for array assignments to the pvar. *)
 let java_get_vararg_values node pvar idenv =
-  let values = ref [] in
-  let do_instr = function
+  let values_of_instr acc = function
     | Sil.Store (Exp.Lindex (array_exp, _), _, content_exp, _)
       when Exp.equal (Exp.Lvar pvar) (Idenv.expand_expr idenv array_exp) ->
         (* Each vararg argument is an assignment to a pvar denoting an array of objects. *)
-        values := content_exp :: !values
+        content_exp :: acc
     | _ ->
-        ()
+        acc
   in
-  let do_node n = List.iter ~f:do_instr (Procdesc.Node.get_instrs n) in
-  let () =
-    match Errdesc.find_program_variable_assignment node pvar with
-    | Some (node', _) ->
-        Procdesc.iter_slope_range do_node node' node
-    | None ->
-        ()
+  let values_of_node acc n =
+    Procdesc.Node.get_instrs n |> List.fold ~f:values_of_instr ~init:acc
   in
-  !values
+  match Errdesc.find_program_variable_assignment node pvar with
+  | Some (node', _) ->
+      Procdesc.fold_slope_range node' node ~f:values_of_node ~init:[]
+  | None ->
+      []
 
 
 let proc_calls resolve_attributes pdesc filter : (Typ.Procname.t * ProcAttributes.t) list =