console.log (Object.prototype.toString.call([].__proto__));
console.log (Object.prototype.toString.call([].__proto__.__proto__));
console.log (Object.prototype.toString.call([].__proto__.__proto__.__proto__));
console.log (Object.prototype.toString.call([].__proto__.__proto__.__proto__));
console.log (Object.prototype.toString.call([].__proto__.__proto__.__proto__.__proto__));

console.log (Object.prototype.toString.call([].__proto__));
console.log (Object.prototype.toString.call([].__proto__.__proto__));
console.log (Object.prototype.toString.call([].__proto__.__proto__.__proto__));

remove duplicate line, and we aren't testing exceptions here so don't deref null.