1 files changed, 1 insertions, 1 deletions
diff --git a/iseq.h b/iseq.h
index b4008c384b..487b703c80 100644
--- a/iseq.h
+++ b/iseq.h
@@ -23,7 +23,7 @@ VALUE rb_iseq_build_from_ary(rb_iseq_t *iseq, VALUE misc,
 			     VALUE exception, VALUE body);
 
 /* iseq.c */
-void rb_iseq_add_mark_object(rb_iseq_t *iseq, VALUE obj);
+void rb_iseq_add_mark_object(const rb_iseq_t *iseq, VALUE obj);
 VALUE rb_iseq_load(VALUE data, VALUE parent, VALUE opt);
 VALUE rb_iseq_parameters(const rb_iseq_t *iseq, int is_proc);
 struct st_table *ruby_insn_make_insn_table(void);