validatepasswords.html

<div formGroupName="matching_passwords">
  <mat-form-field class="full-width">
    <input matInput type="password" placeholder="Password" formControlName="password" required>
    <mat-error *ngFor="let validation of account_validation_messages.password">
      <mat-error class="error-message" *ngIf="accountDetailsForm.get('matching_passwords').get('password').hasError(validation.type) && (accountDetailsForm.get('matching_passwords').get('password').dirty || accountDetailsForm.get('matching_passwords').get('password').touched)">{{validation.message}}</mat-error>
    </mat-error>
  </mat-form-field>

  <mat-form-field class="full-width">
    <input matInput type="password" placeholder="Confirm Password" formControlName="confirm_password"  [errorStateMatcher]="parentErrorStateMatcher" required>
    <mat-error *ngFor="let validation of account_validation_messages.confirm_password">
      <mat-error class="error-message" *ngIf="(accountDetailsForm.get('matching_passwords').get('confirm_password').hasError(validation.type)|| accountDetailsForm.get('matching_passwords').hasError(validation.type)) && (accountDetailsForm.get('matching_passwords').get('confirm_password').dirty || accountDetailsForm.get('matching_passwords').get('confirm_password').touched)">{{validation.message}}</mat-error>
    </mat-error>
  </mat-form-field>

</div>