While working on this upgrade, I got an error that does not make sense to me

328 Call to static method PHPUnit\Framework\Assert::assertCount() with 0
and array{array<string, mixed>} will always evaluate to false.
🪪 staticMethod.impossibleType
💡 Because the type is coming from a PHPDoc, you can turn off this
check by setting treatPhpDocTypesAsCertain: false in your
phpstan.neon.dist.

Without this extension, PHPStan seems to work just fine in that it doesn't do this change to the return type:

-list<array<string,mixed>>
+array{array<string, mixed>}

I'm reported this here because this change happens as soon as I enable this extension in the config:

    - vendor/phpstan/phpstan-phpunit/extension.neon