title: Does Angular allow nested steppers?
body: <p>I'm trying to nest Angular Material steppers, to better model business logic (forms and other step contents elided for brevity):</p>
  
  <pre><code>&lt;mat-vertical-stepper [linear]="true" #main_stepper&gt;
    &lt;mat-step state="quote"&gt;
      &lt;ng-template matStepLabel&gt;
        &lt;strong&gt;What do you need?&lt;/strong&gt;
      &lt;/ng-template&gt;
      &lt;mat-vertical-stepper
        [linear]="true"
        #quote_stepper&gt;
        &lt;mat-step state="how"&gt;
          &lt;ng-template matStepLabel&gt;
            &lt;strong&gt;How?&lt;/strong&gt;
          &lt;/ng-template&gt;
        &lt;/mat-step&gt;
        &lt;mat-step state="where"&gt;
          &lt;ng-template matStepLabel&gt;
            &lt;strong&gt;Where?&lt;/strong&gt;
          &lt;/ng-template&gt;
        &lt;/mat-step&gt;
        &lt;mat-step state="what"&gt;
          &lt;ng-template matStepLabel&gt;
            &lt;strong&gt;What?&lt;/strong&gt;
          &lt;/ng-template&gt;
        &lt;/mat-step&gt;
        &lt;mat-step state="who"&gt;
          &lt;ng-template matStepLabel&gt;
            &lt;strong&gt;Who?&lt;/strong&gt;
          &lt;/ng-template&gt;
        &lt;/mat-step&gt;
      &lt;/mat-vertical-stepper&gt;
    &lt;/mat-step&gt;
    &lt;mat-step state="choose"&gt;
      &lt;ng-template matStepLabel&gt;
        &lt;strong&gt;Which offer would you like?&lt;/strong&gt;
      &lt;/ng-template&gt;
    &lt;/mat-step&gt;
    &lt;mat-step state="review"&gt;
      &lt;ng-template matStepLabel&gt;
        &lt;strong&gt;Review and submit your chosen offer&lt;/strong&gt;
      &lt;/ng-template&gt;
    &lt;/mat-step&gt;
  &lt;/mat-vertical-stepper&gt;
  </code></pre>
  
  <p>The steps for the nested stepper are being rendered in <em>both</em> the inner <em>and</em> the outer steppers:</p>
  
  <p><a href="https://i.stack.imgur.com/Bsq69.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Bsq69.png" alt="Stepper rendering"></a></p>
  
  <p>So..</p>
  
  <ol>
  <li>Am I doing something wrong here?</li>
  <li>Is there a better way to accomplish what I'm after?</li>
  </ol>