PHP Fatal error: Cannot use positional argument after argument unpacking

Goal

I would like to write a function with variable number of parameters (using ...) that calls another function with the same arguments and a new one at the end. Order is important! The example below is just for demonstration.

What I tried

function foo(...$params) {    $extraVariable = 6;    var_dump(...$params, $extraVariable);}foo(2, 4, 1, 4);

Problem

When I run it, I get the following error message:

PHP Fatal error: Cannot use positional argument after argument unpacking in /home/user/main.php on line 3

How can I achieve my goal?