False positive when working with ArrayAccess

[BladeMF]

This code fails with the error ... expects ArrayAccess<int, covariant object>, Doctrine\Common\Collections\ArrayCollection<int, stdClass> given.

[ondrejmirtes]

You should be able to reproduce that problem in the playground, not sure why you can't.

[BladeMF]

Is that extension installed there?

[ondrejmirtes]

AFAIK there is nothing special in the extension you can't reproduce on the playground. Just stub files.

[BladeMF]

But if I remove the extension the error goes away. Would you like me to test something specific? I can try and dig in deeper?

[ondrejmirtes]

What if you only include the related stub files from extension.neon here?

If you're not successful in reproducing the issue on the playground, you should be able to reproduce it in a small repository where you can include the phpstan-doctrine extension.

[BladeMF]

I found it, gimme a second to find the stub and link it.

[BladeMF]

This |null causes it:

phpstan-doctrine/stubs/Collections/Collection.stub

Line 13 in 0871900

* @extends ArrayAccess<TKey|null, T>

[ondrejmirtes]

Can you reproduce it on the playground now?

[BladeMF]

This is the original Collection:

/**
 * @psalm-template TKey of array-key
 * @psalm-template T
 * @template-extends ReadableCollection<TKey, T>
 * @template-extends ArrayAccess<TKey, T>
 */
interface Collection extends ReadableCollection, ArrayAccess

this is the stub:

/**
 * @template TKey of array-key
 * @template T
 * @extends IteratorAggregate<TKey, T>
 * @extends ArrayAccess<TKey|null, T>
 * @extends ReadableCollection<TKey, T>
 */
interface Collection extends Countable, IteratorAggregate, ArrayAccess, ReadableCollection

[BladeMF]

Also, Countable, IteratorAggregate is redundant here as ReadableCollection extends them.

[ondrejmirtes]

Not on older Doctrine versions.

[BladeMF]

Touche. Is the null there as well?

[ondrejmirtes]

Please reproduce the problem on the playground or in a small repository so I can evaluate whether the problem is valid or not.

[BladeMF]

https://phpstan.org/r/ce3ebe06-1a2c-4e3c-a282-77e79ef43937

[ondrejmirtes]

Summoning our variance expert @jiripudil here: what do you think, is this a legit errror? https://phpstan.org/r/ce3ebe06-1a2c-4e3c-a282-77e79ef43937

Thanks 😊