InvalidArrayAccess

The [key] bracket access syntax is used on a value whose type does not support it. Only arrays, strings, and objects implementing ArrayAccess (or Countable/Traversable in some contexts) support bracket access.

Example

<?php
function first(int $value): mixed {
    return $value[0]; // int does not support array access
}

How to fix

Ensure the value is an array, string, or ArrayAccess before using bracket notation.