test262/test/language/statements/for-in/scope-body-lex-boundary.js
Mike Pennisi 3b3bd06819 Add tests for Lexical Environment management
Add tests that assert the management of the running execution context's
LexicalEnvironment and VariableEnvironment components, as created by the
following abstract operations:

- NewDeclarativeEnvironment
- NewObjectEnvironment
- NewFunctionEnvironment

Many tests require the use of non-strict direct eval, meaning they may
not be run in strict mode. This does not effect coverage because the
semantics in these cases are not observable from strict mode code.

Some situations require the creation of a binding, but this binding has
no relevance to the test itself. In these cases, use names consisting
solely of the underscore character (`_`).

Avoid the use of Block statements wherever possible, as these trigger
the creation of additional environments which may interfere with the
behavior under test.
2016-04-28 09:44:41 -04:00

51 lines
1.5 KiB
JavaScript

// Copyright (C) 2016 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation
description: >
Creation of new lexical environment for each evaluation of the statement
body
info: |
IterationStatement : for ( ForDeclaration of AssignmentExpression ) Statement
[...]
2. Return ? ForIn/OfBodyEvaluation(ForDeclaration, Statement, keyResult,
lexicalBinding, labelSet).
13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation
[...]
5. Repeat
[...]
i. Let result be the result of evaluating stmt.
j. Set the running execution context's LexicalEnvironment to oldEnv.
k. If LoopContinues(result, labelSet) is false, return ?
IteratorClose(iterator, UpdateEmpty(result, V)).
l. If result.[[Value]] is not empty, let V be result.[[Value]].
features: [let]
---*/
let x = 'outside';
var probeFirst, probeSecond;
for (let x in { a: 0, b: 0 })
if (!probeFirst)
probeFirst = function() { return x; };
else
probeSecond = function() { return x; };
// 13.7.5.15 EnumerateObjectProperties
//
// > [...] The mechanics and order of enumerating the properties is not
// > specified [...]
assert.notSameValue(probeFirst(), probeSecond());
assert(
probeFirst() === 'a' || probeFirst() === 'b',
'First binding is either "a" or "b"'
);
assert(
probeSecond() === 'a' || probeSecond() === 'b',
'Second binding is either "a" or "b"'
);