title: React functional component static property
body: <p>I had a class component with another class component as his static property.
  Now I switched to a function component and I don't know how to keep the static property.</p>
  
  <pre><code>class Panel extends React.Component&lt;Props&gt; {
    public static Fieldset = PanelFieldset;
  }
  
  class PanelFieldset extends React.Component&lt;Props&gt; {
    ...
  }
  
  class App extends React.Component&lt;Props&gt; {
    public render() {
      return (
        &lt;Panel&gt;
          &lt;Panel.Fieldset&gt;
            ...
          &lt;/Panel.Fieldset&gt;
        &lt;/Panel&gt;
      )
    }
  }
  </code></pre>
  
  <p>Now, switching to function component:</p>
  
  <pre><code>const Panel: React.FunctionComponent&lt;Props&gt; = (props) =&gt; {
    Panel.Fieldset = PanelFieldset;
  }
  </code></pre>
  
  <p>but I get the error:
  Property 'Fieldset' does not exist on type 'FunctionComponent'.ts(2339)</p>
  
  <p>Any help?</p>