| // 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. |
| |
| class Element {} |
| |
| class Class<E extends Element?> { |
| E? element; |
| |
| Class(this.element); |
| |
| void setElement(E? element) { |
| if (this.element != element) { |
| this.element = element; |
| Set<Element> elements = new Set<Element>(); |
| if (element != null) { |
| elements.add(element); |
| } |
| if (this.element != null) { |
| elements.add(this.element!); |
| } |
| } |
| } |
| } |
| |
| main() {} |