// 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 the initial 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 [...] d. If lhsKind is either assignment or varBinding, then [...] e. Else, i. Assert: lhsKind is lexicalBinding. ii. Assert: lhs is a ForDeclaration. iii. Let iterationEnv be NewDeclarativeEnvironment(oldEnv). iv. Perform BindingInstantiation for lhs passing iterationEnv as the argument. v. Set the running execution context's LexicalEnvironment to iterationEnv. [...] features: [let] ---*/ var probeBefore = function() { return x; }; let x = 'outside'; var probeExpr, probeDecl, probeBody; for ( let [x, _ = probeDecl = function() { return x; }] in { i: probeExpr = function() { typeof x; }} ) probeBody = function() { return x; }; assert.sameValue(probeBefore(), 'outside'); assert.throws(ReferenceError, probeExpr); assert.sameValue(probeDecl(), 'i', 'reference from ForDeclaration'); assert.sameValue(probeBody(), 'i', 'reference from statement body');