Hi,

the info node "(gnus) Client-Side IMAP Splitting" says:

    ‘nnimap-split-methods’
         Uses the same syntax as ‘nnmail-split-methods’ [...]

OK, the same syntax as nnmail-split-methods. Then later in the same node
there is an example where the same variable is given a value with
_fancy_ splitting syntax:

         (nnimap "imap.example.com"
                 (nnimap-inbox "INBOX")
                 (nnimap-split-methods
                  (| ("MailScanner-SpamCheck" "spam" "spam.detected")
                     (to "foo@bar.com" "foo")
                     "undecided")))

Clearly a documentation bug. So maybe: