Thread:Project:Support desk/is the current page in a special category?/reply (5)

Indeed, there's no such thing as #isincategory. I only used it in my example because the OP did as well. "At the time the above code is executed, MediaWiki just does not (or not yet) know, which categories the article is in." This is true, and it can't know in time because of the above paradox.