Rule normalize_index_brace Array index should always be written by using square braces. Examples Example #1 --- Original +++ New <?php -echo $sample{$index}; +echo $sample[$index]; Rule sets The rule is part of the following rule sets: @PHP74Migration @PHP80Migration @PHP81Migration @PHP82Migration @PhpCsFixer @Symfony Source class PhpCsFixer\Fixer\ArrayNotation\NormalizeIndexBraceFixer