Revert "Cleanup instanceof Type checks"

[takaram]

This partially reverts 3b72271 (#4380).

Closes phpstan/phpstan#13694

[staabm]

looks like this fix regresses phpstan/phpstan#8372 which was fixed recently
see https://github.com/phpstan/phpstan-src/actions/runs/18634779784#summary-53124523776

[takaram]

@staabm
Was it really fixed? I tested on latest 2.1.x and still see the error Cannot access an offset on mixed.

[staabm]

Was it really fixed?

hmm seems you are right. even on the latest dev-2.1.x it does not look fixed. maybe a issue-bot bug then.

➜ phpstan-src git:(2.1.x) ✗ php bin/phpstan analyze test.php --debug --level=10 Xdebug: [Step Debug] Could not connect to debugging client. Tried: localhost:9003 (through xdebug.client_host/xdebug.client_port). ! [NOTE] The Xdebug PHP extension is active, but "--xdebug" is not used. ! The process was restarted and it will not halt at breakpoints. ! Use "--xdebug" if you want to halt at breakpoints. Note: Using configuration file /Users/m.staab/dvl/phpstan-src/phpstan.neon.dist. /Users/m.staab/dvl/phpstan-src/test.php ------ --------------------------------------- Line test.php ------ --------------------------------------- 2 Class Test must be abstract or final. 🪪 phpstan.finalClass at test.php:2 21 Cannot access an offset on mixed. 🪪 offsetAccess.nonOffsetAccessible at test.php:21 22 Cannot access an offset on mixed. 🪪 offsetAccess.nonOffsetAccessible at test.php:22 ------ ---------------------------------------