test262/test/language/expressions/delete/11.4.1-5-2.js

// Copyright (c) 2012 Ecma International.  All rights reserved.
// Ecma International makes this code available under the terms and conditions set
// forth on http://hg.ecmascript.org/tests/test262/raw-file/tip/LICENSE (the
// "Use Terms").   Any redistribution of this code must retain the above
// copyright and this notice and otherwise comply with the Use Terms.

/*---
es5id: 11.4.1-5-2
description: >
    delete operator returns false when deleting a direct reference to
    a function argument
flags: [noStrict]
includes: [runTestCase.js]
---*/

function testcase() {
  
  function foo(a,b) {
  
    // Now, deleting 'a' directly should fail
    // because 'a' is direct reference to a function argument;
    var d = delete a;
    return (d === false && a === 1);
  }
  return foo(1,2);  
 }
runTestCase(testcase);