Paul Berry
df7c4bb439
This an experimental change; we haven't yet decided whether we want to allow this. See https://github.com/dart-lang/language/issues/2939 for discussion. Bug: https://github.com/dart-lang/language/issues/2939 Change-Id: If69ab66d18ae7ec3dfc79496ce13517ef1c15227 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/290907 Reviewed-by: Konstantin Shcheglov <scheglov@google.com> Commit-Queue: Paul Berry <paulberry@google.com> Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
32 lines
1008 B
Dart
32 lines
1008 B
Dart
// Copyright (c) 2023, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// SharedOptions=--enable-experiment=patterns,records
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/// Test that switch expressions are allowed to be empty, and that they have the
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/// proper static type behavior.
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///
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/// Note that the runtime behavior only matters in mixed-mode programs, since in
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/// fully sound programs an empty switch expression will be unreachable.
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import '../static_type_helper.dart';
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// Note: no subtypes.
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sealed class A {}
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Never emptySwitchOnSealedClass(A a) =>
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(switch (a) { })..expectStaticType<Never>();
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void unreachableAfterEmptySwitch(A a, int? i) {
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if (i == null) {
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(switch (a) { });
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// Flow analysis should understand that since `switch (a) {}` has type
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// `Never`, the rest of this block is unreachable.
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}
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// Hence, `i` is promoted to non-nullable.
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i.isEven;
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}
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main() {}
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