LanguageFeatures/nnbd/flow-analysis/reachability_break_A02_t03.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 Break statement: If N is a statement of the form break [L];, then:
 *
 *  Let S be the statement targeted by the break. If L is not present, this is
 *  the innermost do, for, switch, or while statement. Otherwise it is the do,
 *  for, switch, or while statement with a label matching L.
 *
 *  Update break(S) = join(break(S), before(N)).
 *
 *  Let after(N) = unreachable(before(N)).
 *
 * @description Checks reachability after break statement. Test while loop and a
 * label. Outer loop is do
 *
 * @author sgrekhov@unipro.ru
 */
// Requirements=nnbd-strong
import "../../../Utils/expect.dart";

main() {
  late int i;
  outerLoop:
  do {
    while (true) {
      break outerLoop;
      i = 42; // Variable is initialized in a dead code
    }
  } while (false);
  try {
    // 'i' is treated here by flow analysis as possibly assigned, so it is a
    // runtime (not a compile time) error to read it
    i;
    Expect.fail("Error expected");
  } on Error {
    // Ok, expected
  }
}