Debugger entered--Lisp error: (quit)
  accept-process-output(#<process *tramp/sudo *> 1 nil)
  tramp-accept-process-output(#<process *tramp/sudo *> 1)
  tramp-wait-for-output()
  tramp-open-connection-setup-interactive-shell(#<process *tramp/sudo *> nil "sudo" nil "")
  tramp-open-connection-su(nil "sudo" nil "")
  tramp-maybe-open-connection(nil "sudo" nil "")
  tramp-send-command(nil "sudo" nil "" "( test -d / 2>/dev/null; echo tramp_exit_status $? )")
  tramp-send-command-and-check(nil "sudo" nil "" "test -d /" t)
  tramp-handle-file-directory-p("/sudo::/")
  apply(tramp-handle-file-directory-p "/sudo::/")
  tramp-sh-file-name-handler(file-directory-p "/sudo::/")
  apply(tramp-sh-file-name-handler file-directory-p "/sudo::/")
  tramp-file-name-handler(file-directory-p "/sudo::/")
  file-directory-p("/sudo::/")
  find-file-noselect("/sudo::/" nil nil nil)
  find-file("/sudo::/")
  command-line-1(("-eval" "(setq tramp-debug-buffer t)" "-f" "toggle-debug-on-quit" "/sudo::/"))
  command-line()
  normal-top-level()