Kevin Millikin
65b19ffa3c
Translate assert statements in async functions. The translation of
the condition subexpression can produce a sequence of statements that
have been hoisted out of it. These need to be guarded so they are
executed only when asserts are enabled.
For this purpose, we introduce an AssertBlock. The semantics of the
assert block:
assert { s0; ...; sn; }
is the same as:
if (assertsEnabled) { s0; ...; sn; }
where assertsEnabled is a more primitive nullary expression that is
true iff. assertions are enabled. We chose not to encode this using a
construct like assertsEnabled because (1) we would have to support it
appearing as an arbitrary expression which we don't currently need
and (2) it requires deeper pattern matching to detect and skip the
guarded code when desired.
The translation is more complicated because if there is a message
subexpression in an assert, it is conditionally evaluated only if the
assert's condition is false.
Fixes https://github.com/dart-lang/sdk/issues/28498
Change-Id: I0912a57104ede3160533e49f65b6fb79b76f1500
Reviewed-on: https://dart-review.googlesource.com/46442
Commit-Queue: Kevin Millikin <kmillikin@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
30 lines
768 B
Dart
30 lines
768 B
Dart
// Copyright (c) 2018, 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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// The Kernel async transformer should not skip assert statements.
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import 'dart:async';
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import 'package:expect/expect.dart';
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import 'package:async_helper/async_helper.dart';
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g() async => 21;
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f() async => 42;
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test() async {
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assert(await g() == await f());
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}
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main() {
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bool ok = true;
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assert(!(ok = false));
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// !ok iff asserts are enabled.
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asyncStart();
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test().then((_) => Expect.isTrue(ok), onError: (error) {
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// !ok implies error is AssertionError.
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Expect.isTrue(ok || error is AssertionError);
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}).whenComplete(asyncEnd);
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}
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