|  | // Copyright (c) 2020, 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. | 
|  |  | 
|  | abstract class A { | 
|  | void method(dynamic a); | 
|  | } | 
|  |  | 
|  | abstract class B { | 
|  | void method(covariant num a); | 
|  | } | 
|  |  | 
|  | abstract class C { | 
|  | void method(covariant int a); | 
|  | } | 
|  |  | 
|  | abstract class D1 implements A, B, C {} | 
|  |  | 
|  | abstract class D2 implements A, B {} | 
|  |  | 
|  | abstract class D3 implements B, C {} | 
|  |  | 
|  | abstract class D4 implements C, B {} | 
|  |  | 
|  | abstract class D5 implements A, C {} | 
|  |  | 
|  | abstract class E { | 
|  | void method(num a); | 
|  | } | 
|  |  | 
|  | abstract class F { | 
|  | void method(covariant int a); | 
|  | } | 
|  |  | 
|  | abstract class G1 implements E, F {} | 
|  |  | 
|  | abstract class G2 implements F, E {} | 
|  |  | 
|  | main() {} |