// Copyright (C) 2015 André Bargull. All rights reserved. // This code is governed by the BSD license found in the LICENSE file. /*--- info: Mapped arguments object with non-configurable property description: > Mapped arguments property is changed to non-configurable and non-writable. Perform property attribute changes with two [[DefineOwnProperty]] calls. Add intervening call to SetMutableBinding. flags: [noStrict] ---*/ function argumentsNonConfigurableThenNonWritableWithInterveningSetMutableBinding(a) { Object.defineProperty(arguments, "0", {configurable: false}); a = 2; Object.defineProperty(arguments, "0", {writable: false}); assert.sameValue(a, 2); // `arguments[0] === 1` per ES2015, Rev 38, April 14, 2015 Final Draft. // Specification bug: https://bugs.ecmascript.org/show_bug.cgi?id=4371 assert.sameValue(arguments[0], 2); // Postcondition: Arguments mapping is removed. a = 3; assert.sameValue(a, 3); assert.sameValue(arguments[0], 2); } argumentsNonConfigurableThenNonWritableWithInterveningSetMutableBinding(1);