diff --git a/gc.c b/gc.c
index 1bb78add2a..f90bdd99bf 100644
--- a/gc.c
+++ b/gc.c
@@ -4982,8 +4982,8 @@ gc_mark_children(rb_objspace_t *objspace, VALUE obj)
       case T_CLASS:
       case T_MODULE:
 	mark_m_tbl(objspace, RCLASS_M_TBL(obj));
-        if (RCLASS_SUPER((VALUE)obj)) {
-            gc_mark(objspace, RCLASS_SUPER((VALUE)obj));
+        if (RCLASS_SUPER(obj)) {
+            gc_mark(objspace, RCLASS_SUPER(obj));
         }
 	if (!RCLASS_EXT(obj)) break;
         mark_tbl_no_pin(objspace, RCLASS_IV_TBL(obj));
@@ -4994,8 +4994,8 @@ gc_mark_children(rb_objspace_t *objspace, VALUE obj)
 	if (FL_TEST(obj, RICLASS_IS_ORIGIN)) {
 	    mark_m_tbl(objspace, RCLASS_M_TBL(obj));
 	}
-        if (RCLASS_SUPER((VALUE)obj)) {
-            gc_mark(objspace, RCLASS_SUPER((VALUE)obj));
+        if (RCLASS_SUPER(obj)) {
+            gc_mark(objspace, RCLASS_SUPER(obj));
         }
 	if (!RCLASS_EXT(obj)) break;
 	mark_m_tbl(objspace, RCLASS_CALLABLE_M_TBL(obj));