diff --git a/ChangeLog b/ChangeLog
index dc86c6decb..8c6f436832 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Dec 10 13:39:27 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* struct.c (define_aref_method, define_aset_method): use iseq
+	  VALUE instead of rb_iseq_t to prevent from GC, as RB_GC_GUARD
+	  makes sense only for local variables.  [Feature #10575]
+
 Wed Dec 10 09:38:40 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* thread.c (exec_recursive): use the same last method name as
diff --git a/iseq.c b/iseq.c
index 15d1de698c..742083f8a7 100644
--- a/iseq.c
+++ b/iseq.c
@@ -548,7 +548,7 @@ iseq_load(VALUE self, VALUE data, VALUE parent, VALUE opt)
     return iseqval;
 }
 
-rb_iseq_t *
+VALUE
 rb_method_for_self_aref(VALUE name, VALUE arg)
 {
     VALUE iseqval = iseq_alloc(rb_cISeq);
@@ -591,10 +591,10 @@ rb_method_for_self_aref(VALUE name, VALUE arg)
     rb_iseq_build_from_ary(iseq, misc, locals, params, exception, body);
     cleanup_iseq_build(iseq);
 
-    return iseq;
+    return iseqval;
 }
 
-rb_iseq_t *
+VALUE
 rb_method_for_self_aset(VALUE name, VALUE arg)
 {
     VALUE iseqval = iseq_alloc(rb_cISeq);
@@ -646,7 +646,7 @@ rb_method_for_self_aset(VALUE name, VALUE arg)
     rb_iseq_build_from_ary(iseq, misc, locals, params, exception, body);
     cleanup_iseq_build(iseq);
 
-    return iseq;
+    return iseqval;
 }
 
 /*
diff --git a/struct.c b/struct.c
index 3a2ea47434..080c0f3f04 100644
--- a/struct.c
+++ b/struct.c
@@ -13,8 +13,8 @@
 #include "vm_core.h"
 #include "method.h"
 
-rb_iseq_t *rb_method_for_self_aref(VALUE name, VALUE arg);
-rb_iseq_t *rb_method_for_self_aset(VALUE name, VALUE arg);
+VALUE rb_method_for_self_aref(VALUE name, VALUE arg);
+VALUE rb_method_for_self_aset(VALUE name, VALUE arg);
 
 VALUE rb_cStruct;
 static ID id_members;
@@ -175,19 +175,21 @@ new_struct(VALUE name, VALUE super)
 static void
 define_aref_method(VALUE nstr, VALUE name, VALUE off)
 {
-    rb_iseq_t *iseq = rb_method_for_self_aref(name, off);
+    VALUE iseqval = rb_method_for_self_aref(name, off);
+    rb_iseq_t *iseq = DATA_PTR(iseqval);
 
     rb_add_method(nstr, SYM2ID(name), VM_METHOD_TYPE_ISEQ, iseq, NOEX_PUBLIC);
-    RB_GC_GUARD(iseq->self);
+    RB_GC_GUARD(iseqval);
 }
 
 static void
 define_aset_method(VALUE nstr, VALUE name, VALUE off)
 {
-    rb_iseq_t *iseq = rb_method_for_self_aset(name, off);
+    VALUE iseqval = rb_method_for_self_aset(name, off);
+    rb_iseq_t *iseq = DATA_PTR(iseqval);
 
     rb_add_method(nstr, SYM2ID(name), VM_METHOD_TYPE_ISEQ, iseq, NOEX_PUBLIC);
-    RB_GC_GUARD(iseq->self);
+    RB_GC_GUARD(iseqval);
 }
 
 static VALUE