--- a/devtools/server/actors/script.js
+++ b/devtools/server/actors/script.js
@@ -1956,21 +1956,17 @@ const ThreadActor = ActorClassWithSpec(t
         // this call will replace the previous set of source actors for this source
         // with a new one. If the source actors have not been replaced by the time
         // we try to reset the breakpoints below, their location objects will still
         // point to the old set of source actors, which point to different
         // scripts.
         this.unsafeSynchronize(sourceActorsCreated);
       }
 
-      for (let _actor of bpActors) {
-        // XXX bug 1142115: We do async work in here, so we need to create a fresh
-        // binding because for/of does not yet do that in SpiderMonkey.
-        let actor = _actor;
-
+      for (const actor of bpActors) {
         if (actor.isPending) {
           promises.push(actor.originalLocation.originalSourceActor._setBreakpoint(actor));
         } else {
           promises.push(
             this.sources.getAllGeneratedLocations(actor.originalLocation).then(
               (generatedLocations) => {
                 if (generatedLocations.length > 0 &&
                     generatedLocations[0].generatedSourceActor