JSTests/test262/test/language/arguments-object/mapped/nonconfigurable-nonwritable-descriptors-set-by-param.js

// Copyright (C) 2017 Caio Lima. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
description: Mapped arguments property descriptor change to non-configurable and non-writable
info: |
    Mapping just stop working when property is set to non-writable. Change the
    descriptor using [[DefineOwnProperty]] to {configurable: false}, set a = 2 and then
    change property descriptor to {writable: false}. The descriptor's value is
    the one set before the property be configured as {writable: false}.
flags: [noStrict]
esid: sec-arguments-exotic-objects-defineownproperty-p-desc
includes: [propertyHelper.js]
---*/

function fn(a) {
  Object.defineProperty(arguments, "0", {configurable: false});
  a = 2;
  Object.defineProperty(arguments, "0", {writable: false});

  let propertyDescriptor = Object.getOwnPropertyDescriptor(arguments, "0");
  assert.sameValue(propertyDescriptor.value, 2);
  verifyEnumerable(arguments, "0");
  verifyNotWritable(arguments, "0");
  verifyNotConfigurable(arguments, "0");

  // Postcondition: Arguments mapping is removed.
  a = 3;
  propertyDescriptor = Object.getOwnPropertyDescriptor(arguments, "0");
  assert.sameValue(propertyDescriptor.value, 2);
  verifyEnumerable(arguments, "0");
  verifyNotWritable(arguments, "0");
  verifyNotConfigurable(arguments, "0");
}
fn(1);