1 files changed, 1 insertions, 0 deletions
diff --git a/py/map.c b/py/map.c
index 2570941bf..676c364da 100644
--- a/py/map.c
+++ b/py/map.c
@@ -177,6 +177,7 @@ mp_map_elem_t *mp_map_lookup(mp_map_t *map, mp_obj_t index, mp_map_lookup_kind_t
                     --map->used;
                     memmove(elem, elem + 1, (top - elem - 1) * sizeof(*elem));
                     // put the found element after the end so the caller can access it if needed
+                    // note: caller must NULL the value so the GC can clean up (e.g. see dict_get_helper).
                     elem = &map->table[map->used];
                     elem->key = MP_OBJ_NULL;
                     elem->value = value;