Warning: Undefined variable $foo in I:\www\pvcUtils\vendor\friendsofphp\php-cs-fixer\tests\Fixtures\Integration\set\@PHP74Migration-risky.test-in.php on line 7

Fatal error: Uncaught TypeError: implode(): Argument #1 ($separator) must be of type array|string, null given in I:\www\pvcUtils\vendor\friendsofphp\php-cs-fixer\tests\Fixtures\Integration\set\@PHP74Migration-risky.test-in.php:7 Stack trace: #0 I:\www\pvcUtils\vendor\friendsofphp\php-cs-fixer\tests\Fixtures\Integration\set\@PHP74Migration-risky.test-in.php(7): implode(NULL, '') #1 {main} thrown in I:\www\pvcUtils\vendor\friendsofphp\php-cs-fixer\tests\Fixtures\Integration\set\@PHP74Migration-risky.test-in.php on line 7