flycheck: the function ‘cl-defstruct’ is not known to be defined. (emacs-lisp)

Question

How do I fix this? cl-defstruct is an autoloaded macro in /usr/local/share/emacs/28.2/lisp/emacs-lisp/cl-macs.elc, which is definitely in my load path (checked under an emacs session started with emacs -Q).

I already have flycheck-emacs-lisp-load-path set to inherit, and I can see the ...lisp/emacs-lisp directory in my load-path.

Similarly, let* and if-let*, also under that path are hidden from flycheck.

Answer 1

TLDR:
You need (require cl-lib) before you use cl-defstruct in your library (or wherever you use cl-defstruct).

Rationale:
Check the bottom of cl-macs.el. There will you find:

;; Local variables:
;; generated-autoload-file: "cl-loaddefs.el"
;; End:

I.e., the autoloads go into cl-loaddefs.el.

Now check cl-lib.el. There you will find:

(unless (load "cl-loaddefs" 'noerror 'quiet)
  ;; When bootstrapping, cl-loaddefs hasn't been built yet!
  (require 'cl-macs)
  (require 'cl-seq))

Only the (load "cl-loaddefs" 'noerror 'quiet) is really interesting for us. This makes the autoloads from cl-loaddefs known to Emacs.