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:

 <?php
 
-$fn = function (...$args) {
-    return array_sum($args);
-};
+$fn = array_sum(...);
 
 $fn(1, 2, 3);

PHP snippet to change

<?php

$fn = function (...$args) {
    return array_sum($args);
};

$fn(1, 2, 3);

Applied Rules:

FunctionLikeToFirstClassCallableRector

Not a change you expect?

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

Config rector.php

<?php

declare(strict_types=1);

use Rector\CodingStyle\Rector\FunctionLike\FunctionLikeToFirstClassCallableRector;
use Rector\Config\RectorConfig;

return RectorConfig::configure()
    ->withRules([FunctionLikeToFirstClassCallableRector::class]);

Rector version: b855ff - released at 2026-01-22 19:37