Prevent repetitive recursive scanning of dicts when making them long-lived

1 files changed, 3 insertions, 1 deletions

diff --git a/py/obj.h b/py/obj.h
index d086d3c14..8e95983f0 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -359,7 +359,9 @@ typedef struct _mp_map_t {
     size_t all_keys_are_qstrs : 1;
     size_t is_fixed : 1;    // a fixed array that can't be modified; must also be ordered
     size_t is_ordered : 1;  // an ordered array
-    size_t used : (8 * sizeof(size_t) - 3);
+    size_t scanning : 1;    // true if we're in the middle of scanning linked dictionaries,
+                            // e.g., make_dict_long_lived()
+    size_t used : (8 * sizeof(size_t) - 4);
     size_t alloc;
     mp_map_elem_t *table;
 } mp_map_t;