diff --git a/rector.php b/rector.php
index 81ea966..08ef5b7 100644
--- a/rector.php
+++ b/rector.php
@@ -172,7 +172,9 @@
     ]);
 
     $rectorConfig->rules([
+        BooleanInBooleanNotRuleFixerRector::class,
         InlineConstructorDefaultToPropertyRector::class,
+        StaticClosureRector::class,
     ]);
 
     $rectorConfig->ruleWithConfiguration(RenameFunctionRector::class, [
diff --git a/src/Support/helpers.php b/src/Support/helpers.php
index 010b4b8..4aadcf9 100644
--- a/src/Support/helpers.php
+++ b/src/Support/helpers.php
@@ -14,11 +14,9 @@
     /**
      * @param mixed $expression
      *
-     * @return string|void
-     *
      * @noinspection DebugFunctionUsageInspection
      */
-    function var_output($expression, bool $return = false)
+    function var_output($expression, bool $return = false): ?string
     {
         $patterns = [
             "/array \\(\n\\)/" => '[]',
@@ -36,6 +34,8 @@ function var_output($expression, bool $return = false)
         }
 
         echo $export;
+
+        return null;
     }
 }