diff --git a/infer/src/IR/Exp.ml b/infer/src/IR/Exp.ml
index d135a38cf..39d7c9ed1 100644
--- a/infer/src/IR/Exp.ml
+++ b/infer/src/IR/Exp.ml
@@ -173,30 +173,6 @@ let le e1 e2 = BinOp (Le, e1, e2)
 (** Create expression [e1 < e2] *)
 let lt e1 e2 = BinOp (Lt, e1, e2)
 
-(** Extract the ids and pvars from an expression *)
-let get_vars exp =
-  let rec get_vars_ exp vars =
-    match exp with
-    | Lvar pvar ->
-        (fst vars, pvar :: snd vars)
-    | Var id ->
-        (id :: fst vars, snd vars)
-    | Cast (_, e) | UnOp (_, e, _) | Lfield (e, _, _) | Exn e | Sizeof {dynamic_length= Some e} ->
-        get_vars_ e vars
-    | BinOp (_, e1, e2) | Lindex (e1, e2) ->
-        get_vars_ e1 vars |> get_vars_ e2
-    | Closure {captured_vars} ->
-        List.fold
-          ~f:(fun vars_acc (captured_exp, _, _) -> get_vars_ captured_exp vars_acc)
-          ~init:vars captured_vars
-    | Const (Cint _ | Cfun _ | Cstr _ | Cfloat _ | Cclass _) ->
-        vars
-    | Sizeof _ ->
-        vars
-  in
-  get_vars_ exp ([], [])
-
-
 let fold_captured ~f exp acc =
   let rec fold_captured_ exp captured_acc =
     match exp with
diff --git a/infer/src/IR/Exp.mli b/infer/src/IR/Exp.mli
index bdd83e950..aefe78b80 100644
--- a/infer/src/IR/Exp.mli
+++ b/infer/src/IR/Exp.mli
@@ -116,9 +116,6 @@ val le : t -> t -> t
 val lt : t -> t -> t
 (** Create expression [e1 < e2] *)
 
-val get_vars : t -> Ident.t list * Pvar.t list
-(** Extract the ids and pvars from an expression *)
-
 val free_vars : t -> Ident.t Sequence.t
 (** all the idents appearing in the expression *)
 
diff --git a/infer/src/checkers/Siof.ml b/infer/src/checkers/Siof.ml
index 8c52577bd..618a071e0 100644
--- a/infer/src/checkers/Siof.ml
+++ b/infer/src/checkers/Siof.ml
@@ -82,7 +82,9 @@ module TransferFunctions (CFG : ProcCfg.S) = struct
       Pvar.is_global pv && not (Pvar.is_static_local pv) && not (Pvar.is_pod pv)
       && not (Pvar.is_compile_constant pv) && not (is_compile_time_constructed pdesc pv)
     in
-    Exp.get_vars e |> snd |> List.filter ~f:is_dangerous_global |> GlobalVarSet.of_list
+    Exp.program_vars e
+    |> Sequence.fold ~init:GlobalVarSet.empty ~f:(fun gset g ->
+           if is_dangerous_global g then GlobalVarSet.add g gset else gset )
 
 
   let filter_global_accesses initialized =
diff --git a/infer/src/checkers/liveness.ml b/infer/src/checkers/liveness.ml
index 25de8447e..e3268b5af 100644
--- a/infer/src/checkers/liveness.ml
+++ b/infer/src/checkers/liveness.ml
@@ -24,15 +24,15 @@ module TransferFunctions (CFG : ProcCfg.S) = struct
 
   type extras = ProcData.no_extras
 
-  (* add all of the vars read in [exp] to the live set *)
+  (** add all of the vars read in [exp] to the live set *)
   let exp_add_live exp astate =
-    let ids, pvars = Exp.get_vars exp in
     let astate' =
-      List.fold ~f:(fun astate_acc id -> Domain.add (Var.of_id id) astate_acc) ~init:astate ids
+      Exp.free_vars exp
+      |> Sequence.fold ~init:astate ~f:(fun astate_acc id -> Domain.add (Var.of_id id) astate_acc)
     in
-    List.fold
-      ~f:(fun astate_acc pvar -> Domain.add (Var.of_pvar pvar) astate_acc)
-      ~init:astate' pvars
+    Exp.program_vars exp
+    |> Sequence.fold ~init:astate' ~f:(fun astate_acc pvar ->
+           Domain.add (Var.of_pvar pvar) astate_acc )
 
 
   let add_live_actuals actuals call_exp live_acc =