diff --git a/ChangeLog b/ChangeLog
index 3b6bd48e51..3b43b1cea1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Sat Nov 14 02:19:16 2015  Koichi Sasada  <ko1@atdot.net>
+
+	* method.h: constify rb_cref_t::scope_visi;
+
+	* eval_intern.h (CREF_SCOPE_VISI_COPY): catch up this fix.
+
+	* vm_method.c: ditto.
+
 Sat Nov 14 01:53:52 2015  Naohisa Goto  <ngotogenome@gmail.com>
 
 	* pack.c (pack_unpack, AVOID_CC_BUG): Very ugly workaround for
diff --git a/eval_intern.h b/eval_intern.h
index 6b5ca7fe60..d78bb39f08 100644
--- a/eval_intern.h
+++ b/eval_intern.h
@@ -216,7 +216,7 @@ static inline void
 CREF_SCOPE_VISI_COPY(rb_cref_t *dst_cref, const rb_cref_t *src_cref)
 {
     const rb_scope_visibility_t *src = &src_cref->scope_visi;
-    rb_scope_visibility_t *dst = &dst_cref->scope_visi;
+    rb_scope_visibility_t *dst = (rb_scope_visibility_t *)&dst_cref->scope_visi; /* OK for const cast */
 
     dst->method_visi = src->method_visi;
     dst->module_func = src->module_func;
diff --git a/method.h b/method.h
index 21a02bc7d0..d36cf38297 100644
--- a/method.h
+++ b/method.h
@@ -42,7 +42,7 @@ typedef struct rb_cref_struct {
     const VALUE refinements;
     const VALUE klass;
     struct rb_cref_struct * const next;
-    rb_scope_visibility_t scope_visi;
+    const rb_scope_visibility_t scope_visi;
 } rb_cref_t;
 
 /* method data type */
diff --git a/vm_method.c b/vm_method.c
index 7d658b003e..6c2137b7b3 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -1048,20 +1048,24 @@ rb_scope_module_func_check(void)
     return CREF_SCOPE_VISI(rb_vm_cref())->module_func;
 }
 
+static void
+vm_cref_set_visibility(rb_method_visibility_t method_visi, int module_func)
+{
+    rb_scope_visibility_t *scope_visi = (rb_scope_visibility_t *)&rb_vm_cref()->scope_visi;
+    scope_visi->method_visi = method_visi;
+    scope_visi->module_func = module_func;
+}
+
 void
 rb_scope_visibility_set(rb_method_visibility_t visi)
 {
-    rb_scope_visibility_t *scope_visi = &rb_vm_cref()->scope_visi;
-    scope_visi->method_visi = visi;
-    scope_visi->module_func = FALSE;
+    vm_cref_set_visibility(visi, FALSE);
 }
 
 static void
 rb_scope_module_func_set(void)
 {
-    rb_scope_visibility_t *scope_visi = &rb_vm_cref()->scope_visi;
-    scope_visi->method_visi = METHOD_VISI_PRIVATE;
-    scope_visi->module_func = TRUE;
+    vm_cref_set_visibility(METHOD_VISI_PRIVATE, TRUE);
 }
 
 void