ConfigResolver.php
public function processArguments(array $arguments) : array
    {
        foreach ($arguments as $key => $value) {
            if (is_string($value) && 0 === strpos($value, '@')) {
                $name = substr($value, 1);

                if (isset($this->contextCallbacks[$name])) {
                    $arguments[$key] = call_user_func($this->contextCallbacks[$name]);
                }
            }
        }

        return $arguments;
    }
public function processArguments(array $arguments) : array
    {
        foreach ($arguments as $key => $value) {
            if (is_string($value) && 0 === strpos($value, '@')) {
                $name = substr($value, 1);

                if (isset($this->contextCallbacks[$name])) {
                    $arguments[$key] = call_user_func($this->contextCallbacks[$name]);
                }
            }
        }

        return $arguments;
    }
@param array $arguments

@return array