Language/Expressions/Property_Extraction/conditional_t01.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). Extracted property is in the superclass
 * @author sgrekhov@unipro.ru
 */
import '../../../Utils/expect.dart';

class A {
  String id = "id";
}

class C extends A {
}

main() {
  var c1 = new C() as C?;
  C? c2 = null;
  Expect.equals("id", c1?.id);
  Expect.isNull(c2?.id);
}