ES: Fix small bug

src/host/c/es.c

@@ -27,7 +27,7 @@
  *      need to force a drop)
  * - Crash on overflow (keep the basic negative rank approach for now, 
  *   optimizing this is not a priority)
- * - Tag Ribbit's 3 roots for faster collectable check? 
+ * - Tag Ribbit's 3 roots for faster collectable check?
  * - Benchmarks for the new adoption scheme and dirtiness check
  * - Ref count (make sure all non-cyclic ribs are collected, adapt io and sys
  *   primitives, apply, ... you know, make it work)
@@ -1518,7 +1518,7 @@ void push2(obj car, obj tag) {
   if (IS_RIB(old_stack)) {
     get_field(new_rib, 4) = get_parent(old_stack);
     get_parent(old_stack) = stack;
-    set_rank(stack, alloc_rank+1);    
+    set_rank(old_stack, alloc_rank+1);
   }
   alloc_rank--;