bug#44968: 28.0.50; [feature/native-comp] Emacs segfault in `rustic-flycheck-dirs-list'

[Andrea Corallo]

Reported by Gerry Agbobada,

reproducer:

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;; -*- lexical-binding: t -*-

(defun rustic-flycheck-dirs-list (start end)
  "Return a list of directories from START (inclusive) to END (exclusive).
E.g., if START is '/a/b/c/d' and END is '/a', return the list
'(/a/b/c/d /a/b/c /a/b) in this order.
START and END are strings representing file paths.  END should be
above START in the file hierarchy; if not, the list stops at the
root of the file hierarchy."
  (let ((dirlist)
        (dir (expand-file-name start))
        (end (expand-file-name end)))
    (while (not (or (equal dir (car dirlist)) ; avoid infinite loop
                    (file-equal-p dir end)))
      (push dir dirlist)
      (setq dir (directory-file-name (file-name-directory dir))))
    (nreverse dirlist)))

(native-compile #'rustic-flycheck-dirs-list)

(message "%s" (rustic-flycheck-dirs-list "/tmp/test/foo" "/tmp"))

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