diff --git a/array.h b/array.h
index 4f44716..ef14aee 100644
--- a/array.h
+++ b/array.h
@@ -45,10 +45,11 @@ rb_klass_is_rary(VALUE klass)
 static inline void
 rary_modify(VALUE ary)
 {
-    if (OBJ_FROZEN(ary)) {
+    const long mask =  RBASIC(ary)->flags;
+    if (mask & FL_FREEZE) {
 	rb_error_frozen("array");
     }
-    if (!OBJ_UNTRUSTED(ary) && rb_safe_level() >= 4) {
+    if (!(mask & FL_UNTRUSTED) && rb_vm_safe_level() >=  4) {
 	rb_raise(rb_eSecurityError, "Insecure: can't modify array");
     }
 }
diff --git a/hash.h b/hash.h
index 1283209..cf636fd 100644
--- a/hash.h
+++ b/hash.h
@@ -41,10 +41,11 @@ rb_klass_is_rhash(VALUE klass)
 static inline void
 rhash_modify(VALUE hash)
 {
-    if (OBJ_FROZEN(hash)) {
+    const long mask =  RBASIC(hash)->flags;
+    if (mask & FL_FREEZE) {
 	rb_error_frozen("hash");
     }
-    if (!OBJ_UNTRUSTED(hash) && rb_safe_level() >=  4) {
+    if (!(mask & FL_UNTRUSTED) && rb_vm_safe_level() >=  4) {
 	rb_raise(rb_eSecurityError, "Insecure: can't modify hash");
     }
 }