Rule dir_constant Replaces dirname(__FILE__) expression with equivalent __DIR__ constant. Warning Using this rule is risky Risky when the function dirname is overridden. Examples Example #1 --- Original +++ New <?php -$a = dirname(__FILE__); +$a = __DIR__; Rule sets The rule is part of the following rule sets: @PhpCsFixer:risky @Symfony:risky Source class PhpCsFixer\Fixer\LanguageConstruct\DirConstantFixer