(defmethod xref-doit ((type (eql :sys-depends-on)) thing)
  "asdf's depends-on first seems to be direct dependencies,
   and the rest is the list of packages"
  (declare (ignorable type))
  (loop for dependency in (rest (first (asdf:component-depends-on 'asdf:operation thing)))
        for asd-file = (asdf:system-definition-pathname dependency)
        when asd-file
        collect (list dependency
                      (swank/backend:make-location
                        `(:file ,(namestring asd-file))
                        `(:position 1)
                        `(:snippet ,(format nil "(defsystem :~A" dependency)
                          :align t)))))