ido-imenu as used in Emacs Rocks #10

gistfile1.el

(defun ido-imenu ()
  "Update the imenu index and then use ido to select a symbol to navigate to.
Symbols matching the text at point are put first in the completion list."
  (interactive)
  (imenu--make-index-alist)
  (let ((name-and-pos '())
        (symbol-names '()))
    (flet ((addsymbols (symbol-list)
                       (when (listp symbol-list)
                         (dolist (symbol symbol-list)
                           (let ((name nil) (position nil))
                             (cond
                              ((and (listp symbol) (imenu--subalist-p symbol))
                               (addsymbols symbol))

                              ((listp symbol)
                               (setq name (car symbol))
                               (setq position (cdr symbol)))

                              ((stringp symbol)
                               (setq name symbol)
                               (setq position (get-text-property 1 'org-imenu-marker symbol))))

                             (unless (or (null position) (null name))
                               (add-to-list 'symbol-names name)
                               (add-to-list 'name-and-pos (cons name position))))))))
      (addsymbols imenu--index-alist))
    ;; If there are matching symbols at point, put them at the beginning of `symbol-names'.
    (let ((symbol-at-point (thing-at-point 'symbol)))
      (when symbol-at-point
        (let* ((regexp (concat (regexp-quote symbol-at-point) "$"))
               (matching-symbols (delq nil (mapcar (lambda (symbol)
                                                     (if (string-match regexp symbol) symbol))
                                                   symbol-names))))
          (when matching-symbols
            (sort matching-symbols (lambda (a b) (> (length a) (length b))))
            (mapc (lambda (symbol) (setq symbol-names (cons symbol (delete symbol symbol-names))))
                  matching-symbols)))))
    (let* ((selected-symbol (ido-completing-read "Symbol? " symbol-names))
           (position (cdr (assoc selected-symbol name-and-pos))))
      (goto-char position))))

Yep, I'm getting the same issue as terranpro. Traceback:

Debugger entered--Lisp error: (wrong-type-argument integer-or-marker-p nil)
  goto-char(nil)
  (cond ((overlayp position) (goto-char (overlay-start position))) (t (goto-char position)))
  (let* ((selected-symbol (if (null a-symbol) (ido-completing-read "Symbol? " symbol-names) a-symbol)) (position (cdr (assoc selected-symbol name-and-pos)))) (cond ((overlayp position) (goto-char (overlay-start position))) (t (goto-char position))))
  (let ((name-and-pos (quote nil)) (symbol-names (quote nil))) (let* ((vnew (function (lambda (symbol-list) (progn (if ... ...))))) (old (if (fboundp (quote addsymbols)) (symbol-function (quote addsymbols)) (quote cl--unbound)))) (unwind-protect (progn (if (eq vnew (quote cl--unbound)) (fmakunbound (quote addsymbols)) (fset (quote addsymbols) vnew)) (addsymbols imenu--index-alist)) (if (eq old (quote cl--unbound)) (fmakunbound (quote addsymbols)) (fset (quote addsymbols) old)))) (let* ((selected-symbol (if (null a-symbol) (ido-completing-read "Symbol? " symbol-names) a-symbol)) (position (cdr (assoc selected-symbol name-and-pos)))) (cond ((overlayp position) (goto-char (overlay-start position))) (t (goto-char position)))))
  ido-goto-symbol(#("Article" 0 7 (fontified t face (highlight-symbol-face))))
  mine-goto-symbol-at-point()
  call-interactively(mine-goto-symbol-at-point record nil)
  command-execute(mine-goto-symbol-at-point record)
  smex-read-and-run(("toggle-debug-on-error" "mine-goto-symbol-at-point" "flycheck-mode" "eval-buffer" "set-variable" "emacs-lisp-mode" "push-button" "vc-annotate" "tags-generate-for-this-repo" "rename-file-and-buffer" "flymake-mode" "whitespace-mode" "copy-for-code-snippet" "smerge-mode" "run-python" "query-replace-regexp" "list-packages" "occur" "git-flow-release-start" "start-scratch-file" "indent-region" "toggle-truncate-lines" "virtualenv-workon" "git-flow-release-push" "yas-reload-all" "which-function-mode" "apropos" "virtualenv-search" "python-insert-super-function" "re-builder" "viper-mode" "paredit-mode" "make-directory" "eshell" "smerge-next" "run-haskell" "query-replace-repeat" "package-list-packages" "next-error" "python-mode" "pylookup-lookup" "fundamental-mode" "package-install" "highlight-symbol-mode" "calc" "js2-mode" "jedi-mode" "electric-pair-mode" "jedi:goto-definition" "html-mode" ...))
  smex()
  call-interactively(smex nil nil)

This occurs when I jump to symbols that have been imported rather than defined in the current file.