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
 
 // imagine this being dynamic, not just a const string..
-$command = 'echo "%s"';
+$command = 'echo "%s"';
+assert(...);
 
-assert(is_string($command));
-passthru(sprintf($command, $foo));
+is_string(...);
+passthru(...);
+sprintf($command, $foo);
     
-echo $command;
+echo $command;

PHP snippet to change

<?php

// imagine this being dynamic, not just a const string..
$command = 'echo "%s"';

assert(is_string($command));
passthru(sprintf($command, $foo));
    
echo $command;

Applied Rules:

Not a change you expect?

Create an issue on GitHub

Config rector.php

<?php

use Rector\Config\RectorConfig;
use Rector\Php85\Rector\Expression\NestedFuncCallsToPipeOperatorRector;
use Rector\DeadCode\Rector\Expression\RemoveDeadStmtRector;
use Rector\ValueObject\PhpVersion;

return RectorConfig::configure()
    ->withRules([
        NestedFuncCallsToPipeOperatorRector::class,
        RemoveDeadStmtRector::class,
    ])
    ->withPhpVersion(PhpVersion::PHP_85);

Rector version: febd1c - released at 2026-04-01 18:25