Typescript Cannot find name 'IterableIterator'
<p>I have problem with my code in typescript
After compile by tsc, I have errors like about cannot find some names.</p>

<pre><code>app.ts(1,22): error TS2304: Cannot find name 'IterableIterator'.
app.ts(8,20): error TS2304: Cannot find name 'IteratorResult'.
app.ts(26,6): error TS2304: Cannot find name 'Symbol'.
app.ts(26,26): error TS2304: Cannot find name 'IterableIterator'.
</code></pre>

<p>My code is:</p>

<pre><code>class Fib implements IterableIterator&lt;number&gt; {
    protected fn1 = 0;
    protected fn2 = 1;

    constructor(protected maxValue?: number) {}

    public next(): IteratorResult&lt;number&gt; {
        var current = this.fn1;
        this.fn1 = this.fn2;
        this.fn2 = current + this.fn1;

        if (this.maxValue &amp;&amp; current &lt;= this.maxValue) {
            return {
                done: false,
                value: current
            }
        }

        return {
            done: true
        }
    }

    [Symbol.iterator](): IterableIterator&lt;number&gt; {
        eturn this;
    }
}

fib = new Fib();
console.log(fib.next());
</code></pre>

<p>version tsc is Version 2.1.0-dev.20160716</p>