Bug report

I am in the process of reproducing a issue we see in rectorphp/rector#4708
in which I try to find out why we get a Unable to resolve the template type T in call to method Rector\\Core\\PhpParser\\Node\\BetterNodeFinder\:\:findFirstParentInstanceOf\(\) error.

while creating a re-production case in the demo sandbox, I can see a error

Internal error: Provided node "Base" is not class, but "interface" Run PHPStan with --debug option and post the stack trace to: https://github.com/phpstan/phpstan/issues/new

I know my code is not "well" but it should at least not crash phpstan :)

Code snippet that reproduces the problem

https://phpstan.org/r/071bc230-81fa-40f4-b1bf-76360cf34e85

Expected output

I guess this shouldn't error that fatal :).

maybe the sandbox should even report the underlying error (run phpstan itself with --debug) - so all information at hand could just be put into this issue.