array.invalidKey

Code example

<?php declare(strict_types = 1);

$key = new stdClass();
$array = [$key => 'value'];

Why is it reported?

The value used as an array key is not a valid array key type. PHP only allows int, string, bool, float, and null as array keys (with bool, float, and null being cast to int or string). Using any other type, such as an object or an array, as an array key results in a fatal error at runtime.

In the example above, an stdClass object is used as an array key, which is not allowed.

How to fix it

Use a valid array key type such as int or string:

 <?php declare(strict_types = 1);

-$key = new stdClass();
-$array = [$key => 'value'];
+$key = 'my_key';
+$array = [$key => 'value'];