Language/Expressions/Property_Extraction/conditional_t05.dart

/*
 * Copyright (c) 2015, 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 Evaluation of a conditional property extraction expression e of
 * the form e1?.id is equivalent to the evaluation of the expression
 * ((x) => x == null?null : x.id)(e1), unless e1 is a type literal, in which
 * case it is equivalent to e1.m.
 * @description Check that e1?.id is equivalent to
 * ((x) => x == null?null : x.id)(e1). Test conditional method extraction
 * @author sgrekhov@unipro.ru
 */
import '../../../Utils/expect.dart';

class A {
  String id1() => "id1";
}

class C extends A {
  String id2() => "id2";
}

main() {
  C c1 = new C();
  C c2 = null;
  Expect.equals(c1.id1, c1?.id1);
  Expect.equals(c1.id2, c1?.id2);

  Expect.isNull(c2?.id1);
  Expect.isNull(c2?.id2);
}