diff --git a/infer/src/checkers/IdAccessPathMapDomain.ml b/infer/src/checkers/IdAccessPathMapDomain.ml
index 7d9098f23..133513c65 100644
--- a/infer/src/checkers/IdAccessPathMapDomain.ml
+++ b/infer/src/checkers/IdAccessPathMapDomain.ml
@@ -18,27 +18,6 @@ include IdMap
 let pp fmt astate =
   IdMap.pp ~pp_value:AccessPath.Raw.pp fmt astate
 
-let (<=) ~lhs ~rhs =
-  if phys_equal lhs rhs
-  then true
-  else
-    try
-      IdMap.for_all
-        (fun id lhs_ap ->
-           let rhs_ap = IdMap.find id rhs in
-           let eq = AccessPath.Raw.equal lhs_ap rhs_ap in
-           if not eq && Config.debug_exceptions
-           then
-             failwithf "Id %a maps to both %a and %a@."
-               Var.pp id
-               AccessPath.Raw.pp lhs_ap
-               AccessPath.Raw.pp rhs_ap;
-           eq)
-        lhs
-    with Not_found -> false
-
-(* in principle, could do a join here if the access paths have the same root. but they should
-   always be equal if we are using the map correctly *)
 let check_invariant ap1 ap2 = function
   | Var.ProgramVar pvar when Pvar.is_frontend_tmp pvar ->
       (* Sawja reuses temporary variables which sometimes breaks this invariant *)
@@ -52,6 +31,18 @@ let check_invariant ap1 ap2 = function
           AccessPath.Raw.pp ap1
           AccessPath.Raw.pp ap2
 
+let (<=) ~lhs ~rhs =
+  if phys_equal lhs rhs
+  then true
+  else
+    IdMap.for_all
+      (fun id lhs_ap ->
+         let rhs_has = IdMap.mem id rhs in
+         if rhs_has && Config.debug_exceptions
+         then check_invariant lhs_ap (IdMap.find id rhs) id;
+         rhs_has)
+      lhs
+
 let join astate1 astate2 =
   if phys_equal astate1 astate2
   then astate1