Non-generic child not compatible with generic parent

[calebdw]

Bug report

Hello!

This issue was raised in Larastan and I was able to replicate it in the PHPStan sandbox.

Code snippet that reproduces the problem

https://phpstan.org/r/4baca60a-d370-46f7-be22-484c603754ab

Expected output

I would expect the Regions collection to be compatible as it does specify the inner types

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[ondrejmirtes]

If you make the Collection @template-covariant, this issue disappears. Of course, a different issue appears.

See: https://phpstan.org/r/f648fc64-2d26-4f2f-abb3-69cfb42c6587

The problem is described in this article: https://phpstan.org/blog/whats-up-with-template-covariant

In short, it's not type-safe to do this.

Also please note if you enable strict-rules, you'll get another error:

Parameter #1 $models (array<int, Region>) of method Region::newCollection() should be contravariant with parameter $models (array) of method Model::newCollection()

Which signifies this design isn't really sound.

[calebdw]

Hmm, I suppose I need to update the newCollection method to not be generic itself:

https://phpstan.org/r/9893cc7c-9b35-4cfc-a4ee-580df25a5261

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