> >> When I byte-compile oauth2.el (0.18), below errors and warnings are
> >> displayed and fail to byte-compiling.
(snip)

> Thanks for the report!  I have now pushed a few fixes which should
> handle those warnings/errors plus a few other fixes.  I have also added
> build checks in Gitlab CI.  Now tagged v0.18.1.  Please help check
> whether those fixes work for you.

I've tested on 0.18.2 and confirmed errors and warnings were fixed,
thank you.
But I have one question.  

In oauth2--update-request-cache, 

> (when host-name
>   (let ((host-name (intern host-name)))
>     (org-plist-delete request-cache host-name)
>     (setq request-cache
>         (plist-put request-cache host-name
>                    `( :access-token ,access-token
>                       :request-timestamp ,request-timestamp)))))
> request-cache)

org-plist-delete returns newly created plist and doesn't modify
arguement PLIST, so it does nothing in the above code.  Moreover,
because next plist-put set new property value, it is no need to delete
old property value explicitly.

Please see attached patch.

-- 
Kazuhiro Ito