title: TypeScript Property 'props' does not exist
body: <p>I have this <code>.tsx</code> file:</p>
  <pre class="lang-js prettyprint-override"><code>import React, { Component } from 'react';
  
  export class SidebarItem extends Component {
    constructor(props) {
      super(props);
    }
    
    render() {
      return (&lt;li&gt;{this.props.children}&lt;/li&gt;);
    }
  }
  </code></pre>
  <p>However, TypeScript throws this error:</p>
  <pre><code>error TS2339: Property 'props' does not exist on type 'SidebarItem'.
  </code></pre>