Use MRB_ENV_STACK_LEN instead of accessing `flags` directly to get REnv's stack length.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/gc.c b/src/gc.c
index 81b234d6f..426a84514 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -518,7 +518,7 @@ gc_mark_children(mrb_state *mrb, struct RBasic *obj)
       if (e->cioff < 0) {
         int i, len;
 
-        len = (int)e->flags;
+        len = (int)MRB_ENV_STACK_LEN(e);
         for (i=0; i<len; i++) {
           mrb_gc_mark_value(mrb, e->stack[i]);
         }