Bug report

When an instanceof check is used on a variable typed as object, PHPStan incorrectly infers its type as the concrete class (T) instead of the correct intersection type (object&T). This leads to a false-positive with a subsequent is_subclass_of() check since PHPStan believes that the same type is being supplied to its first and second parameters.

Consult the linked test snippet for more detail about the erroneous pattern.

Code snippet that reproduces the problem

https://phpstan.org/r/25c06554-9cd6-42ea-bd30-d86dc12d94b6

Expected output

Line 	Error
6 	
Dumped type: object
Non-ignorable
8 	
Dumped type: object&stdClass
Non-ignorable

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