src/common/fast-path.js/call
FastPath.prototype.call = function call(callback /*, name1, name2, ... */) {
  const s = this.stack;
  const origLen = s.length;
  let value = s[origLen - 1];
  const argc = arguments.length;
  for (let i = 1; i < argc; ++i) {
    const name = arguments[i];
    value = value[name];
    s.push(name, value);
  }
  const result = callback(this);
  s.length = origLen;
  return result;
};