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// Copyright (c) 2019, 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 Dynamic Semantics
/// The new dynamic semantics are a superset of the original behavior. To avoid
/// redundancy and handle nested uses, the semantics are expressed in terms of a
/// separate procedure below:
/// Lists
/// 1. Create a fresh instance [collection] of a class that implements [List<E>].
/// An implementation is, of course, free to optimize by pre-allocating a list
/// of the correct capacity when its size is statically known. Note that when
/// [if] and [for] come into play, it's no longer always possible to
/// statically tell the final size of the resulting flattened list.
/// 2. For each [element] in the list literal:
/// i. Evaluate [element] using the procedure below.
/// 3. The result of the literal expression is [collection].
/// . . .
/// To evaluate a collection [element]:
/// This procedure handles elements in both list and map literals because the
/// only difference is how a base expression element or entry element is handled.
/// The control flow parts are the same so are unified here.
/// . . .
/// 3. Else, if [element] is an asynchronous [await for-in] element:
/// i. Evaluate the stream expression to a value [stream]. It is a dynamic
/// error if [stream] is not an instance of a class that implements
/// [Stream].
/// ii. Create a new [Future], [streamDone].
/// iii. Evaluate [await streamDone].
/// iv. Listen to [stream]. On each data event [event] the stream sends:
/// a. If the [for-in] element declares a variable, create a fresh
/// [variable] for it. Otherwise, use the existing [variable] it
/// refers to.
/// b. Bind [event] to [variable].
/// c. Evaluate the body element using this procedure in the scope of
/// [variable]. If this raises an exception, complete [streamDone]
/// with it as an error.
/// v. If the [for-in] element declares a variable, discard it.
/// vi. If [stream] raises an exception, complete [streamDone] with it as an
/// error. Otherwise, when all events in the stream are in the stream are
/// processed, complete [streamDone] with [null].
/// . . .
/// @description Checks that if [element] of list literal is a an asynchronous
/// [await for-in] element, this element is evaluated using the specified
/// procedure.
/// @author
import "dart:async";
import "../../Utils/expect.dart";
main() async {
var l1 = [1, 2];
var l2 = [null, 4.1, false];
var list1exp = [1, 2, null, 4.1, false];
var s1 = new Stream.fromIterable(l1);
var s2 = new Stream.fromIterable(l2);
var list1 = [await for (var v in s1) v, await for (var v in s2) v];
Expect.isTrue(list1 is List<Object?>);
Expect.listEquals(list1exp, list1);