title: How to display a mat-error message without a form control, but with matInput?
body: <p>I have this code in my <code>Material table</code>:</p>
  
  <pre><code>&lt;ng-container matColumnDef="columnDef"&gt;
     &lt;th mat-header-cell *matHeaderCellDef&gt;Column heading&lt;/th&gt;
     &lt;td mat-cell *matCellDef="let row"&gt;
         &lt;mat-form-field&gt;
               &lt;input matInput [(ngModel)]="row.myField"&gt;
               &lt;mat-error *ngIf="row.myField &gt; 0"&gt; My error message &lt;/mat-error&gt;
          &lt;/mat-form-field&gt;
     &lt;/td&gt;
  &lt;/ng-container&gt;
  </code></pre>
  
  <p>The thing is that mat-form-field is not a <code>FormControl</code>, but it would be nice if <code>mat-error</code> would somehow validate this input and display the error message.</p>
  
  <p>Can someone tell me if it is possible?</p>