diff --git a/framework/filters/AccessRule.php b/framework/filters/AccessRule.php
index a1c243e9292..066bf4fa838 100644
--- a/framework/filters/AccessRule.php
+++ b/framework/filters/AccessRule.php
@@ -98,18 +98,33 @@ class AccessRule extends Component
      * The map indicates query parameters that will be passed when determining
      * role access.
      * 
-     * If only a value is passed then the query parameter will by passed as is.
-     * If both a key and value are passed, then the name of the parameter will
-     * be changed. A value of `['a' => 'b']` will invoke [[User::can()]] with
-     * the content of queryParam['a'] as key 'b' in the params argument.
+     * If both a key and a value are passed, then the name of the parameter will
+     * be changed. A value of `['a' => 'b']` will cause [[User::can()]] to be
+     * invoked with the content of queryParam['a'] as key 'b' in the params
+     * argument.
+     * If only a value is passed then it is equivalent to passing the same value
+     * as key.
      * 
      * The special parameters '{action}' and '{controller}' are bound to the
      * action and controller ids
      */
     public $paramsMap = [];
     
-    
+    /**
+     * @var array the parameters to be passed to [[User::can()]].
+     * 
+     * Do not use directly, use [[getParamsForCan()]] to access it
+     */
     private $_paramsForCan = null;
+    
+    /**
+     * Gets the parameters to be passed to [[User::can()]].
+     * 
+     * It will parse [[AccessRule::paramsMap]] and create the array of
+     * parameters, if it has not been created already.
+     * 
+     * @return array
+     */
     private function getParamsForCan() {
         if ($this->_paramsForCan === null) {
             $newParams = [];
@@ -118,10 +133,10 @@ private function getParamsForCan() {
                 if (!is_string($key)) {
                     $key = $value;
                 }
-                if ($key == '{action}') {
+                if ($key === '{action}') {
                     $newParams[$value] = Yii::$app->controller->action->id;
                 }
-                else if ($key == '{controller}') {
+                elseif ($key === '{controller}') {
                     $newParams[$value] = Yii::$app->controller->id;
                 }
                 if (ArrayHelper::keyExists($key, $queryParams)) {