For discussion, see the following thread:
https://lists.gnu.org/r/emacs-devel/2021-03/msg00119.html
* lisp/emacs-lisp/cl-macs.el (cl--sm-macroexpand): Fix recently
uncovered use of old name for pcase--dontcare.
;; The behavior of CL made sense in a dynamically scoped
;; language, but nowadays, lexical scoping semantics is more often
;; expected.
- (`(,(or 'let 'let*) . ,(or `(,bindings . ,body) dontcare))
+ (`(,(or 'let 'let*) . ,(or `(,bindings . ,body) pcase--dontcare))
(let ((nbs ()) (found nil))
(dolist (binding bindings)
(let* ((var (if (symbolp binding) binding (car binding)))