deps/v8/src/js/array.js
function ArrayFill(value, start, end) {
  CHECK_OBJECT_COERCIBLE(this, "Array.prototype.fill");

  var array = TO_OBJECT(this);
  var length = TO_LENGTH(array.length);

  return InnerArrayFill(value, start, end, array, length);
}
function ArrayFill(value, start, end) {
  CHECK_OBJECT_COERCIBLE(this, "Array.prototype.fill");

  var array = TO_OBJECT(this);
  var length = TO_LENGTH(array.length);

  return InnerArrayFill(value, start, end, array, length);
}
ES6, draft 04-05-14, section 22.1.3.6