PhpCsFixer\RuleSet::resolveSet PHP Method

    private function resolveSet()
    {
        $rules = $this->set;
        $hasSet = null;
        // expand sets
        do {
            $hasSet = false;
            $tmpRules = $rules;
            $rules = array();
            foreach ($tmpRules as $name => $value) {
                if (!$hasSet && '@' === $name[0]) {
                    $hasSet = true;
                    $set = $this->getSetDefinition($name);
                    foreach ($set as $nestedName => $nestedValue) {
                        // if set value is false then disable all fixers in set, if not then get value from set item
                        $rules[$nestedName] = $value ? $nestedValue : false;
                    }
                    continue;
                }
                $rules[$name] = $value;
            }
        } while ($hasSet);
        // filter out all rules that are off
        $rules = array_filter($rules);
        $this->rules = $rules;
        return $this;
    }