new-with-non-object-prototype-failure.js

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// Test failure when constructing a function whose |.prototype| property isn't an object.

function Klass() {

  this.prop = 1;

// Save the original prototype.

const KlassPrototype = Klass.prototype;

// Set the prototype to a non-object value.

Klass.prototype = null;

const prototypes = [

  null,

  KlassPrototype,

];

const N = 500;

let c = 0;

for (let i = 0; i <= N; ++i) {

  // Always perform a set to avoid a cold-code bailout.

  let proto = prototypes[(i === N)|0];

  Klass.prototype = proto;

  // Create a new object.

  let o = new Klass();

  // Read a property from the new object to ensure it was correctly allocated

  // and initialised.

  c += o.prop;

  // The prototype defaults to %Object.prototype% when the |.prototype|

  // property isn't an object.

  assertEq(Object.getPrototypeOf(o), proto === null ? Object.prototype : KlassPrototype);

assertEq(c, N + 1);