we only require this for validation sake
function($scope, element, attrs) {
        var src = attrs.ngMessagesInclude || attrs.src;
        $templateRequest(src).then(function(html) {
          if ($scope.$$destroyed) return;

          if (isString(html) && !html.trim()) {
            // Empty template - nothing to compile
            replaceElementWithMarker(element, src);
          } else {
            // Non-empty template - compile and link
            $compile(html)($scope, function(contents) {
              element.after(contents);
              replaceElementWithMarker(element, src);
            });
          }
        });
      }