If you've ever come across this type of error when you're trying to fetch parameters of the current route:

Symfony\Component\Debug\Exception\FatalThrowableError: Call to member function parameters() on null

It's probably because the route doesn't exist, which is why it failed to call the parameters() function. It can be easily resolved by checking if the route exists before calling the function:

<?php
namespace App\Http\Controllers;
use Route;

class FooController extends Controller {
    public function __construct(Request $request){
        // insert code here...
    }

    public function foo(Request $request){
        $params = $request->route() ? Route::current()->parameters() : '';
        return $params;
    }
}
?>

Although, the sample code above is to fetch parameters of the current route, you can apply this before calling any method from the Route class.

This works for version 5.2 and above.