[sledge] Fix order of Exp.fold args

Reviewed By: ngorogiannis

Differential Revision: D14251654

fbshipit-source-id: 8d1e22da7

sledge/src/llair/exp.ml

@@ -1039,17 +1039,13 @@ let iter e ~f =
 
 let fold e ~init:s ~f =
   match e with
-  | App {op; arg} ->
-      let s = f s op in
-      let s = f s arg in
-      s
+  | App {op; arg} -> f op (f arg s)
   | Add {args} | Mul {args} ->
-      let s = Qset.fold ~f:(fun e _ s -> f s e) args ~init:s in
-      s
+      Qset.fold ~f:(fun e _ s -> f e s) args ~init:s
   | _ -> s
 
-let for_all e ~f = fold ~f:(fun so_far a -> so_far && f a) ~init:true e
-let exists e ~f = fold ~f:(fun found a -> found || f a) ~init:false e
+let for_all e ~f = fold ~f:(fun a so_far -> so_far && f a) ~init:true e
+let exists e ~f = fold ~f:(fun a found -> found || f a) ~init:false e
 
 let app1 ?(partial = false) op arg =
   ( match (op, arg) with

sledge/src/llair/exp.mli

@@ -204,7 +204,7 @@ val offset : t -> (Q.t * Typ.t) option
 val iter : t -> f:(t -> unit) -> unit
 val fold_vars : t -> init:'a -> f:('a -> Var.t -> 'a) -> 'a
 val fold_exps : t -> init:'a -> f:('a -> t -> 'a) -> 'a
-val fold : t -> init:'a -> f:('a -> t -> 'a) -> 'a
+val fold : t -> init:'a -> f:(t -> 'a -> 'a) -> 'a
 val for_all : t -> f:(t -> bool) -> bool
 val exists : t -> f:(t -> bool) -> bool
 

sledge/src/symbheap/congruence.ml

@@ -551,7 +551,7 @@ let rec norm_extend r ek =
           ~default:e
           ~if_added:(fun lkp ->
             let use =
-              Exp.fold e_' ~init:r.use ~f:(fun use b'j ->
+              Exp.fold e_' ~init:r.use ~f:(fun b'j use ->
                   let b' = Exp.base b'j in
                   Map.update use b' ~f:(function
                     | Some b_use -> Use.add b_use e