LanguageFeatures/nnbd/weak/syntax_A06_t01.dart

// 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.

/// @assertion The grammar of selectors is extended to allow null-aware
/// subscripting using the syntax e1?[e2] which evaluates to null if e1
/// evaluates to null and otherwise evaluates as e1[e2].
///
/// @description Check that the grammar of selectors is extended to allow
/// null-aware subscripting using the syntax e1?[e2] which evaluates to null if
/// e1 evaluates to null and otherwise evaluates as e1[e2].
/// @author sgrekhov@unipro.ru
/// @issue 39865

// Requirements=nnbd-weak

import "../../../Utils/expect.dart";

class C {
  int operator[](int index) => index * 2;
}

main() {
  C? c = null;
  Expect.isNull(c?[42]);
  c = new C();
  Expect.equals(4, c?[2]);
//                  ^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//                 ^
// [cfe] Operand of null-aware operation '?.' has type 'C' which excludes null.
}