title: MatToolbar throws error when using it with Angular 9
body: <p>Angular version 9.2.0</p>
  
  <p>When I import the <code>MatToolbarModule</code> in a module and use it in the html template, then I get the following error message:</p>
  
  <blockquote>
    <p>This likely means that the library (@angular/material/toolbar) which declares MatToolbarModule has not been processed correctly by ngcc, or is not compatible with Angular Ivy. Check if a newer version of the library is available, and update if so. Also consider checking with the library's authors to see if the library is expected to be compatible with Ivy.</p>
  
  <pre><code>8 export declare class MatToolbarModule {
                         ~~~~~~~~~~~~~~~~
  src/app/angular-material.module.ts:53:14 - error NG6002: Appears in the NgModule.imports of ComponentsModule, but itself has errors
  </code></pre>
  </blockquote>
  
  <p>Does anyone face the same issue?</p>