Thanks for spotting this. Yes you are right. My local branch
was very different from the one on ELPA and it did not use
nadvice package. Recently I merged ELPA version back and the
code segment you highlighted was quite old and I don't even
remember what it's for, probably a transition code during the
period of transition from `xxx' to `cl-xxx' ...
I've fixed it along with an issue found on the Windows version
-- I just found that the Windows version is a convenient tool to
help me test old Emacs versions like Emacs 24.2.
Thanks.