bug#67609: 29.1; (eglot-inlay-hints-mode -1) behaves surprisingly, does not work in cc-mode hooks

[Morgon Kanter]

Hi João,

> Hi.  Because you're using 'eglot-ensure' (hint, maybe you
> shoudn't, read the manual in the latest master for why)
> it means that after the eglot-ensure form executes,
> Eglot will not be setup yet, so the following form
> has no effect.  You need to replace it with [snip]

I believe there is more to the story than this. I can remove the
eglot-ensure, load eglot so eglot-inlay-hints-mode is a valid symbol,
and replace my config with this:

(defun config:cc-defaults ()
  ;(setq c-require-final-newline t)  ;; lol causes errors in cc-mode
  (c-toggle-comment-style 1)
  (subword-mode 1)
  (diminish 'subword-mode)
  (local-set-key (kbd "C-M-S-<backspace>") #'kill-outer-sexp-and-parens)
  (eglot-inlay-hints-mode -1))

...and I will receive the same behavior. The eglot-ensure here is a red herring.

To reproduce, visit a C++ buffer in a project, run M-x eglot. Inlay
hints will appear. Kill and reopen the buffer. Inlay hints will
appear.

-- Morgon