Bug report

I know that iterating on Generator|null is a bug, but it's not reported until level 7.

When up to level 6, PHPStan does not report a problem and should be able to understand what the iterable type will be in the case where it's not null.

Code snippet that reproduces the problem

https://phpstan.org/r/c9fc2ca5-501f-4fbe-bdcc-cf14a9f12ea9

Expected output

The dumped type should be a union of Block and *ERROR*. It may be an stdClass or it may not be iterable at all.

In addition, an error should be reported on line 18, because neither *ERROR* nor Block has a method called getPos() (definite crash).

Additional notes

I consider this a serious problem because it's an obvious bug that otherwise won't get detected until reaching level 8. This means that reaching level 6 provides a false sense of security while missing problems like this.

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It's greatly assisted me while updating an old project to a newer API.