title: ng-value not working properly
body: <p>In angular 1 ng-value don't work properly with ng-required. When the following code is run it displays that "The input field cannot be empty"
  Although it contains the value of "John".
  When some other value is entered or something is removed from the input field, then the required sentence disappears.</p>
  
  <p>Anybody knows how to solve this?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"&gt;&lt;/script&gt;
  &lt;body ng-app=""&gt;
  
  &lt;form name="myForm"&gt;
  
  Click here to make the input field required:
  
  &lt;div ng-app="" ng-init="firstName='John'"&gt;
  
  &lt;input name="myInput" ng-model="myInput" ng-value="firstName" ng-required="true"&gt;
  
  &lt;h1 ng-if="!myForm.myInput.$valid"&gt;The input field cannot be empty&lt;/h1&gt;
  
  &lt;/form&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;</code></pre>
  </div>
  </div>
  </p>