[AdieuToLogic]

>> The instanceof[0] operator is typically banned from use in application code and often frowned upon in library implementations.

> Never seen this being banned. Whats the reason?

Its usage encodes a priori assumptions of what a super-type could be, often expressed in an "if-else-if tree", thus making the logic doing so needlessly brittle and difficult to maintain.

Library logic sometimes needs to use this construct (I'd argue those abstractions need to be rethought however), but an application which does exhibits a failure in domain modelling IMHO.

[MrBuddyCasino]

It can be a code smell, but there are legitimate uses. This is not something that I would ever "ban".

Over-eager code analyser tools are themselves a "smell", in that you either justifiably or unjustifiably don't trust your developers, trying to make up for their real or perceived deficits with a rather dumb tool. That never goes well in my experience.