v8/test/mjsunit/array-shift2.js

// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Flags: --allow-natives-syntax

Object.defineProperty(Array.prototype, "1", {
  get: function() { return "element 1"; },
  set: function(value) { }
});
function test(array) {
  array.shift();
  return array;
}

%PrepareFunctionForOptimization(test);
var result = test(["0",,2]);
assertEquals(["element 1","element 1"], result);
assertTrue(result.hasOwnProperty("0"));
assertFalse(result.hasOwnProperty("1"));
result = test([{},,{}]);
assertEquals(["element 1","element 1"], result);
assertTrue(result.hasOwnProperty("0"));
assertFalse(result.hasOwnProperty("1"));
%OptimizeFunctionOnNextCall(test);
result = test([{},,0]);
assertEquals(["element 1","element 1"], result);
assertTrue(result.hasOwnProperty("0"));
assertFalse(result.hasOwnProperty("1"));