https://stitcher.io/blog/override-in-php-83

$array = [];

$array[-5] = 'a';

$array[] = 'b';

var_export($array);

//array (

//  -5 => 'a',

//  0 => 'b',

//)

Starting from PHP 8.3, the next item will be added at index -4:

//array (

//  -5 => 'a',

//  -4 => 'b',

//)

Required

I don't think there's anything we can do to automatically detect this, or any way to confirm it.

Creating this issue to:

1. get a second opinion on my analysis of detecting this
2. give us somewhere to link to if we do find instances of it