Badident error when using "as" in ng-repeat - angularjs

Question

I have the following code that filters through a table of results:
<strong>CLIENTS [ {{ results.length }} ]</strong>
<thead ng-show="clientSearch">
<tr>
<th><i class="fa fa-search"></i></th>
<th class="search-box">
<input type="text" placeholder="Search Name" ng-model="searchResult.firstname">
</th>
<th class="search-box">
<input type="text" placeholder="Search Surname" ng-model="searchResult.lastname">
</th>
<th class="search-box">
<input type="text" placeholder="Search Address" ng-model="searchResult.address">
</th>
<th class="search-box">
<input type="text" placeholder="Search Email" ng-model="searchResult.email">
</th>
<th class="search-box">
<input type="number" placeholder="Search Mobile" ng-model="searchResult.mobile">
</th>
<th class="search-box">
<input type="date" class="datepicker" placeholder="Search By Date" ng-model="searchResult.registrationDate">
</th>
</tr>
</thead>
This is the code the produces the table data:
<tr ng-repeat="client in clients as results | filter : searchResult " ng-dblclick="open(client)">
<td>{{$index + 1}}</td>
<td>{{client.firstname}}</td>
<td>{{client.lastname}}</td>
<td>{{client.address}}</td>
<td>{{client.email}}</td>
<td>{{client.mobile}}</td>
<td>{{client.registrationDate | date: 'medium'}}</td>
<td ng-if="results.length === 0">NO RESULTS FOUND</td>
</tr>
But I get this error https://code.angularjs.org/1.3.16/docs/error/ngRepeat/badident when I try to use ngRepeat.
Any suggestions on how I can fix this.