params-dflt-ref-arguments.js (2088B)
1 // Copyright (C) 2016 the V8 project authors. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 /*--- 4 description: Referencing the arguments object from a default parameter (function expression) 5 esid: sec-function-definitions-runtime-semantics-evaluation 6 es6id: 14.1.20 7 features: [default-parameters] 8 info: | 9 FunctionExpression : function ( FormalParameters ) { FunctionBody } 10 11 [...] 12 3. Let closure be FunctionCreate(Normal, FormalParameters, FunctionBody, 13 scope, strict). 14 [...] 15 16 9.2.1 [[Call]] ( thisArgument, argumentsList) 17 18 [...] 19 7. Let result be OrdinaryCallEvaluateBody(F, argumentsList). 20 [...] 21 22 9.2.1.3 OrdinaryCallEvaluateBody ( F, argumentsList ) 23 24 1. Let status be FunctionDeclarationInstantiation(F, argumentsList). 25 [...] 26 27 9.2.12 FunctionDeclarationInstantiation(func, argumentsList) 28 29 [...] 30 23. Let iteratorRecord be Record {[[iterator]]: 31 CreateListIterator(argumentsList), [[done]]: false}. 32 24. If hasDuplicates is true, then 33 [...] 34 25. Else, 35 b. Let formalStatus be IteratorBindingInitialization for formals with 36 iteratorRecord and env as arguments. 37 [...] 38 39 14.1.19 Runtime Semantics: IteratorBindingInitialization 40 41 FormalsList : FormalsList , FormalParameter 42 43 1. Let status be the result of performing IteratorBindingInitialization for 44 FormalsList using iteratorRecord and environment as the arguments. 45 2. ReturnIfAbrupt(status). 46 3. Return the result of performing IteratorBindingInitialization for 47 FormalParameter using iteratorRecord and environment as the arguments. 48 ---*/ 49 50 var callCount = 0; 51 var f; 52 f = function(x = arguments[2], y = arguments[3], z) { 53 assert.sameValue(x, 'third', 'first parameter'); 54 assert.sameValue(y, 'fourth', 'second parameter'); 55 assert.sameValue(z, 'third', 'third parameter'); 56 callCount = callCount + 1; 57 }; 58 59 f(undefined, undefined, 'third', 'fourth'); 60 61 assert.sameValue(callCount, 1, 'function invoked exactly once'); 62 63 reportCompare(0, 0);