LanguageFeatures/nnbd/null_aware_operator_A06_t02.dart

// Copyright (c) 2019, 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 If e1 translates to F then e1?[e2] translates to:
///  SHORT[EXP(e1), fn[x] => x[EXP(e2)]]
///
/// @description Check that if e1 translates to F then e1?[e2] translates to:
///  SHORT[EXP(e1), fn[x] => x[EXP(e2)]]. Test type aliases
/// @author sgrekhov@unipro.ru

// Requirements=nnbd-strong
import '../../Utils/expect.dart';

class C {
  int operator[](int index) => index;
}

typedef CAlias1 = C?;
typedef CAlias2 = C;

void testShort(C? x) {
  var actual1 = x?[42];
  var n0 = x;
  var expected1 = n0 == null ? null : n0[42];
  Expect.equals(expected1, actual1);
}

main() {
  CAlias1 c1 = null;
  testShort(c1);
  c1 = new C();
  testShort(c1);

  CAlias1? c2 = null;
  testShort(c2);
  c2 = new C();
  testShort(c2);

  CAlias2? c3 = null;
  testShort(c3);
  c3 = new C();
  testShort(c3);

  CAlias2 c4 = new C();
  testShort(c4);
}