1 files changed, 1 insertions, 0 deletions
diff --git a/enum.c b/enum.c
index fceed391f6..67d6ee8bf3 100644
--- a/enum.c
+++ b/enum.c
@@ -393,6 +393,7 @@ sort_by_i(i, ary)
 
     v = rb_yield(i);
     e = rb_assoc_new(v, i);
+    OBJ_FREEZE(e);
     rb_ary_push(ary, e);
     return Qnil;
 }