Jenny Messerly
472c898c87
Dart for-in loops allow `var x = [1]; for (var x in x) {}`, which is not
allowed in JS. If this pattern is detected, a temporary variable is
introduced so the for-in initializer expression is evaluated outside of
the JS for-of loop.
(This issue seems to be unique to for-in loops. For loops and other
kinds of variable declarations of the form `var x = ...` are not
allowed to use `x` in the initializer, even if `x` is declared in an
outer scope.)
Also fixes an out-of-date comment in the DDC+Analyzer backend.
Change-Id: I35b272a5a311f7b6f104cc82a99cc83a6ed5c247
Reviewed-on: https://dart-review.googlesource.com/c/79142
Commit-Queue: Alan Knight <alanknight@google.com>
Auto-Submit: Jenny Messerly <jmesserly@google.com>
Reviewed-by: Alan Knight <alanknight@google.com>
65 lines
1.3 KiB
Dart
65 lines
1.3 KiB
Dart
// Copyright (c) 2011, 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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import "package:expect/expect.dart";
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// Dart test for testing for in on a list literal.
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main() {
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testSimple();
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testGenericSyntax1();
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testGenericSyntax2();
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testGenericSyntax3();
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testGenericSyntax4();
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testShadowLocal1();
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testShadowLocal2();
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}
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void testSimple() {
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var list = [1, 3, 5];
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var sum = 0;
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for (var i in list) {
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sum += i;
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}
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Expect.equals(9, sum);
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}
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void testGenericSyntax1() {
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List<List<String>> aCollection = [];
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for (List<String> strArrArr in aCollection) {}
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}
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void testGenericSyntax2() {
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List<List<String>> aCollection = [];
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List<String> strArrArr;
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for (strArrArr in aCollection) {}
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}
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void testGenericSyntax3() {
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List<List<List<String>>> aCollection = [];
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for (List<List<String>> strArrArr in aCollection) {}
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}
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void testGenericSyntax4() {
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List<List<List<String>>> aCollection = [];
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List<List<String>> strArrArr;
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for (strArrArr in aCollection) {}
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}
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void testShadowLocal1() {
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List<int> x = [1, 2, 3];
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var i = 0;
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for (var x in x) {
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Expect.equals(x, ++i);
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}
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}
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void testShadowLocal2() {
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Object x = [1, 2, 3];
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var i = 0;
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for (x in x) {
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Expect.equals(x, ++i);
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}
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}
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