After pressing M-x sly, I keep receiving this message:

[sly] SLIME detected in 'lisp-mode-hook', causes keybinding conflicts. Remove it for this Emacs session?

The odd thing is that SLIME is not installed in MELPA directories like the other packages:

~/.emacs.d/elpa$ ls -l
total 28
-rw-rw-r-- 1 pedro pedro  806 mai 26 16:42 0blayout-readme.txt
drwxrwxr-x 4 pedro pedro 4096 mai 14 17:17 archives
drwx------ 3 pedro pedro 4096 mai 26 16:45 gnupg
drwxrwxr-x 2 pedro pedro 4096 mai 21 20:59 paredit-20191121.2328
drwxrwxr-x 2 pedro pedro 4096 mai 14 17:27 rainbow-blocks-20210412.1937
drwxr-xr-x 6 pedro pedro 4096 mai 22 21:02 sly-20210303.1148
drwxrwxr-x 2 pedro pedro 4096 mai 22 21:18 transpose-frame-20200307.2119

Apparently, it was installed with QuickLisp. After pressing M-x locate-library in Emacs I get:

Library is file ~/.quicklisp/dists/quicklisp/software/slime-v2.26.1/slime.el

This is annoying me because Slime keybindings stopped working recently.

I am new to Common Lisp, Emacs, Sly/Slime, and Quicklisp. Maybe I messed up with stuff.

  • 1
    You'll need to pick one or the other, and remove the config of the other from your ~/.emacs.d/init.el
    – nega
    May 26, 2021 at 21:30
  • thanks, @nega. I think I will stay with Slime. Thus, I will remove sly package. There is just one mention in my .emacs about it. After uninstalling, I guess it will disappear. If it does not go away, I will try manually deleting.This is my configs file github.com/pdelfino/my-emacs-config/blob/main/.emacs May 26, 2021 at 21:41
  • 1
    Yes, that one reference to sly shouldn't pose a problem. It's in a list that custom sets and uses. It should figure things out after you uninstall.
    – nega
    May 26, 2021 at 21:49

1 Answer 1


Both SLIME and SLY are user interfaces for interacting with a running Lisp process. SLY is much newer than SLIME, and so it copies some conventions and key bindings from SLIME. You can’t usefully use both at the same time, so the author of SLY made it check to see if you have SLIME configured as well. This is annoying you, but it would certainly annoy you more if both SLIME and SLY were running and stepping on each other’s all the time.

The right answer here is to disable one and use the other for a while, then swap. Figure out which you prefer and then uninstall the other.

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