False positive: "Use instanceof instead of isset() on object"

[GErpeldinger]

Hello, i've found a new problem when integrating this set of rules in my project, i am on the version dev-main of the package to be sure to have the last change.

I'm experiencing a false positive error with the rule instanceof. Specifically, the error suggests using instanceof instead of isset() on an object property that is not initialized yet.

The bug can be reproduced like this: https://phpstan.org/r/13187976-6dc0-40c3-b86f-f50b50d48dd1

The error message is:

 ------ --------------------------------------------- 
  Line   src/Foo.php                                  
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  24     Use instanceof instead of isset() on object  
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