Array generic type lost after conditionally adding more data into array

[Firehed]

Bug report

When an array contains a generic value at a known index, and then another value is conditionally added (e.g. only if something is non-empty), the type of the first value gets lost. See snippet + expected output for details.

Note that I have the attached template declared as @template-covariant but the issue doesn't seem specific to that.

Code snippet that reproduces the problem

https://phpstan.org/r/f508e2b7-f6f9-4919-8502-cd1a1cdd105a

Expected output

No errors (other than the dumpType() results added to step through the error).

The dumped type on lines 36 and 39 are both correct; observe that the type at the result index changes on line 41, which is incorrect and causes the complaint on the return value.

Also, I've observed that restructuring this to add result after errors does not exhibit this issue. Similarly, not adding errors conditionally behaves as expected from a typechecker perspective (though not what I need at runtime).

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[ondrejmirtes]

Fixed: phpstan/phpstan-src@8342785

[github-actions]

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