src/Dumpling.php
private function inspectClosure($subject)
    {
        $reflection = new ReflectionFunction($subject);
        $params = array_map(function($param) {
            return ($param->isPassedByReference() ? '&$' : '$').$param->name;
        }, $reflection->getParameters());
        $this->result[] = 'Closure ('.implode(", ", $params).') { ... }'."\n";
    }
private function inspectClosure($subject)
    {
        $reflection = new ReflectionFunction($subject);
        $params = array_map(function($param) {
            return ($param->isPassedByReference() ? '&$' : '$').$param->name;
        }, $reflection->getParameters());
        $this->result[] = 'Closure ('.implode(", ", $params).') { ... }'."\n";
    }
Inspired by: http://www.metashock.de/2013/05/dump-source-code-of-closure-in-php/