#993. NativeFunction test added
diff --git a/LibTest/ffi/NativeFunction/NativeFunction_A01_t01.dart b/LibTest/ffi/NativeFunction/NativeFunction_A01_t01.dart
new file mode 100644
index 0000000..fa93d0b
--- /dev/null
+++ b/LibTest/ffi/NativeFunction/NativeFunction_A01_t01.dart
@@ -0,0 +1,37 @@
+// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// @assertion Represents a function type in C.
+///
+/// NativeFunction is not constructible in the Dart code and serves purely as
+/// marker in type signatures.
+///
+/// @description Checks that this class cannot be extended
+/// @author sgrekhov@unipro.ru
+
+import "dart:ffi";
+
+class C1<T extends Function> extends NativeFunction<T> {
+// ^^^^^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+class C2<T extends Function> implements NativeFunction<T> {
+// ^^^^^^^^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+class C3 extends Object with NativeFunction {
+// ^^^^^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+void main() {
+ C1? c1;
+ C2? c2;
+ C3? c3;
+}
