mirror of https://github.com/tc39/test262.git
45 lines
1.6 KiB
JavaScript
45 lines
1.6 KiB
JavaScript
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// Copyright (C) 2016 the V8 project authors. All rights reserved.
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// This code is governed by the BSD license found in the LICENSE file.
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/*---
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esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation
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description: >
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Removal of lexical environment to serve as a temporal dead zone for the
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statement's AssignmentExpresson
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info: |
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IterationStatement : for ( ForDeclaration of AssignmentExpression ) Statement
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1. Let keyResult be the result of performing ?
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ForIn/OfHeadEvaluation(BoundNames of ForDeclaration,
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AssignmentExpression, iterate).
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[...]
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13.7.5.12 Runtime Semantics: ForIn/OfHeadEvaluation
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[...]
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2. If TDZnames is not an empty List, then
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a. Assert: TDZnames has no duplicate entries.
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b. Let TDZ be NewDeclarativeEnvironment(oldEnv).
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c. Let TDZEnvRec be TDZ's EnvironmentRecord.
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d. For each string name in TDZnames, do
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i. Perform ! TDZEnvRec.CreateMutableBinding(name, false).
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e. Set the running execution context's LexicalEnvironment to TDZ.
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3. Let exprRef be the result of evaluating expr.
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4. Set the running execution context's LexicalEnvironment to oldEnv.
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[...]
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features: [let]
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---*/
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let x = 'outside';
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var probeDecl, probeExpr, probeBody;
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for (
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let [x, _ = probeDecl = function() { return x; }]
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of
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(probeExpr = function() { typeof x; }, [['inside']])
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)
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probeBody = function() { return x; };
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assert.throws(ReferenceError, probeExpr);
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assert.sameValue(probeDecl(), 'inside', 'reference from ForDeclaration');
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assert.sameValue(probeBody(), 'inside', 'reference from statement body');
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