Basic Laravel job throws: "Serialization of 'Closure' is not allowed" on failure - php

Question

I have created a very basic queue job:
<?php
namespace App\Jobs;
use Exception;
use Illuminate\Bus\Queueable;
use Illuminate\Queue\SerializesModels;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Foundation\Bus\Dispatchable;
class FailingJob implements ShouldQueue
{
use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;
public $tries = 1;
/**
* Create a new job instance.
*
* #return void
*/
public function __construct()
{
// nothing
}
/**
* Execute the job.
*
* #return void
*/
public function handle()
{
// nothing
}
/**
* Called when the job fails
*
* #param Exception $exception
*/
public function failed(Exception $exception) {
// nothing
}
}
and I dispatch it like so: FailingJob::dispatch();. This works fine.
Now I am purposefully adding "bugged" code in order for the job to fail, but instead of gracefully making the job fail,
I get the following exception:
Serialization of 'Closure' is not allowed.
I'm not sure where this is coming from, because this job is basically empty. I would like to use the failed() function in order to handle failures, but I can't even do that because this exception gets thrown when the job fails.
For reference, this is the code I use to make the job fail:
/**
* Execute the job.
*
* #return void
*/
public function handle()
{
xxxxxx
// ^ This will make the job fail
}