Try Rector Online | Rector - Automated Way to Instantly Upgrade and Refactor any PHP code

Run Rector on your code to see what it can do for you:

         $test = 'Super';
         
         $this->myCallback(
-            function () use ($test) {
-                return compact('test');
-            }
+            fn() => compact('test')
         );
     }

PHP snippet to change

<?php

final class DemoFile
{
    public function run(bool $param)
    {
        $test = 'Super';
        
        $this->myCallback(
            function () use ($test) {
                return compact('test');
            }
        );
    }

    private function myCallback($callback)
    {
        $callback();
    }
}

Applied Rules:

ClosureToArrowFunctionRector

Not a change you expect?

Create an issue on GitHub
...or to speed up fix – add a test fixture

Config rector.php

<?php

use Rector\Config\RectorConfig;
use Rector\Php74\Rector\Closure\ClosureToArrowFunctionRector;
use Rector\ValueObject\PhpVersion;

return RectorConfig::configure()
    ->withRules([
        ClosureToArrowFunctionRector::class
    ])
    // demonstrate specific PHP version
    ->withPhpVersion(PhpVersion::PHP_84);

Rector version: ea5089 - released at 2026-01-27 00:48