DI validation error for a function without parameters

[karan-kang]

I get the following error, when using $inject DI pattern rule for a function without parameters.

C:\Development\MyApp\app\common\helpViewer\helpBtn.directive.js
  15:5  error  You should use the $inject syntax for DI  angular/di

Function Body:
(function() {
'use strict';

angular.module('app.common')
       .directive('appHelpBtn', helpBtn);

/**
 * Help button template generator
 * @name appHelpBtn
 * @memberof app.common
 * @class
 * @example
 * <app-help-btn link="help/something.html"></app-help-btn>
 */
function helpBtn() {
    return {
        restrict: 'AE',
        scope: {
            classes: '@class',
            link: '@'
        },
        template: [
            '<a ng-href="{{link}}" href="#" ng-classes="classes"',
            'title="Show help for this view" app-help-viewer="{{link}}">',
            '<i class="fa fa-lg fa-question"></i>',
            '</a>'
        ].join('')
    };
}

})();

Rule defined in .eslintrc.json file
"angular/di": [ 2, "$inject" ]

Plugins in use
"eslint-config-angular": "~0.5.0"
"eslint-config-google": "~0.7.1"
"eslint-plugin-angular": "~1.6.1"
"gulp-eslint": "~3.0.1",
"gulp": "~3.9.1"

Workaround:
Add this line after declaring the directive.

helpBtn.$inject = [];