LanguageFeatures/nnbd/static_errors_A30_t09.dart

// Copyright (c) 2020, 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 Given a switch statement which switches over an expression e of
/// type T, where the cases are dispatched based on expressions e0...ek:
///
/// - It is no longer required that the ei evaluate to instances of the same
///  class.
/// - It is an error if any of the ei evaluate to a value whose static type is
///  not a subtype of T.
/// - It is an error if any of the ei evaluate to constants for which equality
///  is not primitive.
/// - If T is an enum type, it is a warning if the switch does not handle all
///  enum cases, either explicitly or via a default.
/// - If T is Q? where Q is an enum type, it is a warning if the switch does not
///  handle all enum cases and null, either explicitly or via a default.
///
/// @description Check that it is no warning if T is Q? where Q is an enum type
/// and the switch does handle all enum cases and null explicitly
/// @author sgrekhov@unipro.ru
/// @issue 40394

enum E {
  one,
  two,
  three
}

main() {
  var e = E.three as E?;
  switch (e) {
    case E.one:
      true;
      break;
    case E.two:
      false;
      break;
    case E.three:
      42;
      break;
    case null:
      "42";
  }
}