Robert Nystrom
02b50e4079
Change-Id: Idf369ab6b6ff6784719924fdcc7c586001a285e4 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/148204 Commit-Queue: Bob Nystrom <rnystrom@google.com> Reviewed-by: Erik Ernst <eernst@google.com>
36 lines
1.2 KiB
Dart
36 lines
1.2 KiB
Dart
// TODO(multitest): This was automatically migrated from a multitest and may
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// contain strange or dead code.
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// Copyright (c) 2015, 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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// Verify that '??' binds tighter than '?:' and less tightly than '||'.
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import "package:expect/expect.dart";
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main() {
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// Make sure the "none" test fails if "??" is not implemented. This makes
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// status files easier to maintain.
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var _ = null ?? null;
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dynamic falsity = false;
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dynamic truth = true;
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dynamic one = 1;
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dynamic two = 2;
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dynamic nil = null;
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// "a ?? b ?? c" should be legal, and should evaluate to the first non-null
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// value (or null if there are no non-null values).
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Expect.equals(1, one ?? 2 ?? 3);
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Expect.equals(2, null ?? two ?? 3);
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Expect.equals(3, null ?? null ?? 3);
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Expect.equals(null, null ?? null ?? null);
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// "a ?? b ? c : d" should parse as "(a ?? b) ? c : d", therefore provided
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// that a is true, b need not be a bool. An incorrect parse of
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// "a ?? (b ? c : d)" would require b to be a bool to avoid a static type
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// warning.
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Expect.equals(2, truth ?? one ? 2 : 3);
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}
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