title: Angular Material with features modules and Angular 6
body: <p>I'm having troubles using Angular material with Angular 6 whenever I want to use features modules.
  Here is my project's structure :</p>
  
  <pre><code>app/
  |- app.component.ts
  |- app.component.html
  |- app.module.ts
  |- app-routing.module.ts
  |- homepage/
    |- homepage.module.ts
    |- homepage-routing.module.ts
    |- pages/
      |- homepage.component.html
      |- homepage.component.ts
      |- homepage.component.css
  |- inbox/
    |- inbox.module.ts
    |- inbox-routing.module.ts
    |- pages/
      |- inbox.component.html
      |- inbox.component.ts
      |- inbox.component.css
  </code></pre>
  
  <p>Both inbox and homepage are lazy loaded.
  I'm trying to use Angular Material in both <code>homepage.component.html</code> and <code>inbox.component.html</code> (I want to use MatButtonModule) but failing to do so and the official documentation doesn't help me.</p>
  
  <p>Here is what I tried :</p>
  
  <ul>
  <li>If I try to import MatButtonModule into both <code>homepage.module.ts</code> and <code>inbox.module.ts</code>, the app will crash with this error 
  <code>Uncaught (in promise): TypeError: Cannot read property 'call' of undefined</code>.</li>
  <li>If I try to import MatButtonModule into only one module, it will work only for the component binding to this module.</li>
  <li>If I try to import MatButtonModule directly into <code>app.module.ts</code> it just won't work at all.</li>
  </ul>
  
  <p>So my question is, how can I use Angular Material with features modules, what is the best practices?</p>