PHP arrow functions just stopped working

At some point something happened to my Homestead VM, but I don't know what it was. All of my databases were gone (I have migrations) and now any PHP arrow functions I have in my code produce a Symfony\Component\Debug\Exception\FatalThrowableError exception with the message "syntax error, unexpected '=>' (T_DOUBLE_ARROW), expecting ')'". Switching the code from an arrow function

$job_ids = $jobs->map(fn($job) => $job->role_id)->unique();

back to a callback with typical syntax

$job_ids = $jobs->map(function ($job) { return $job->role_id; })->unique();

fixes the error but arrow functions are spread throughout my code base.

I also tried running an arrow function with artisan tinker and it worked just fine, which make this even more confusing to me.

>>> $collection = collect([1,2,3,4]);
=> Illuminate\Support\Collection {#3366
     all: [
       1,
       2,
       3,
       4,
     ],
   }
>>> $collection->map(fn($item) => $item * 2);
=> Illuminate\Support\Collection {#3357
     all: [
       2,
       4,
       6,
       8,
     ],
   }
>>> 

I'm wondering, is there a command I need to run to refresh something?

ETA: I'm running PHP 7.4.0 and Laravel 6.9.0