Error with completion

[Lars Magne Ingebrigtsen]

If I say `C-h f pop- TAB', then I get the error below.  This is with a
recent bzr checkout, emacs -q, on a machine I haven't tried to compile
bzr emacs before:

Debugger entered--Lisp error: (wrong-type-argument listp 0)
  last((#("pop-to-mark-command" 0 4 (font-lock-face completions-common-part) 4 
5 (font-lock-face completions-first-difference)) #("pop-tag-mark" 0 4 
(font-lock-face completions-common-part) 4 5 (font-lock-face 
completions-first-difference)) #("pop-global-mark" 0 4 (font-lock-face 
completions-common-part) 4 5 (font-lock-face completions-first-difference)) 
#("pop-to-buffer" 0 4 (font-lock-face completions-common-part) 4 5 
(font-lock-face completions-first-difference)) #("pop-mark" 0 4 (font-lock-face 
completions-common-part) 4 5 (font-lock-face completions-first-difference)) . 
0))
  (let* ((last (last (symbol-value (quote --cl-completions--)))) (base-size 
(cdr last)) (display-buffer-mark-dedicated (quote soft))) 
(with-output-to-temp-buffer "*Completions*" (if last (setcdr last nil)) (set 
(quote --cl-completions--) (sort (symbol-value (quote --cl-completions--)) 
(quote string-lessp))) (if completion-annotate-function (set (quote 
--cl-completions--) (mapcar (function (lambda (s) (let ... ...))) (symbol-value 
(quote --cl-completions--))))) (save-current-buffer (set-buffer 
standard-output) (set (make-local-variable (quote completion-base-position)) 
(list (+ (symbol-value (quote --cl-start--)) base-size) nil))) 
(display-completion-list (symbol-value (quote --cl-completions--)))))
  (if (and (symbol-value (quote --cl-completions--)) (or (consp (cdr 
(symbol-value (quote --cl-completions--)))) (not (equal (car (symbol-value 
(quote --cl-completions--))) (symbol-value (quote --cl-string--)))))) (let* 
((last (last (symbol-value (quote --cl-completions--)))) (base-size (cdr last)) 
(display-buffer-mark-dedicated (quote soft))) (with-output-to-temp-buffer 
"*Completions*" (if last (setcdr last nil)) (set (quote --cl-completions--) 
(sort (symbol-value (quote --cl-completions--)) (quote string-lessp))) (if 
completion-annotate-function (set (quote --cl-completions--) (mapcar (function 
(lambda ... ...)) (symbol-value (quote --cl-completions--))))) 
(save-current-buffer (set-buffer standard-output) (set (make-local-variable 
(quote completion-base-position)) (list (+ (symbol-value ...) base-size) nil))) 
(display-completion-list (symbol-value (quote --cl-completions--))))) 
(minibuffer-hide-completions) (ding) (minibuffer-message (if (symbol-value 
(quote --cl-completions--)) "Sole completion" "No completions")))
  (progn (setq a (symbol-value (quote --cl-completions--))) (message nil) (if 
(and (symbol-value (quote --cl-completions--)) (or (consp (cdr (symbol-value 
(quote --cl-completions--)))) (not (equal (car (symbol-value ...)) 
(symbol-value (quote --cl-string--)))))) (let* ((last (last (symbol-value 
(quote --cl-completions--)))) (base-size (cdr last)) 
(display-buffer-mark-dedicated (quote soft))) (with-output-to-temp-buffer 
"*Completions*" (if last (setcdr last nil)) (set (quote --cl-completions--) 
(sort (symbol-value (quote --cl-completions--)) (quote string-lessp))) (if 
completion-annotate-function (set (quote --cl-completions--) (mapcar (function 
...) (symbol-value ...)))) (save-current-buffer (set-buffer standard-output) 
(set (make-local-variable (quote completion-base-position)) (list (+ ... 
base-size) nil))) (display-completion-list (symbol-value (quote 
--cl-completions--))))) (minibuffer-hide-completions) (ding) 
(minibuffer-message (if (symbol-value (quote --cl-completions--)) "Sole 
completion" "No completions"))) nil)
  (let ((--cl-completions-- (completion-all-completions (symbol-value (quote 
--cl-string--)) minibuffer-completion-table minibuffer-completion-predicate (- 
(point) (field-beginning))))) (progn (setq a (symbol-value (quote 
--cl-completions--))) (message nil) (if (and (symbol-value (quote 
--cl-completions--)) (or (consp (cdr (symbol-value ...))) (not (equal (car ...) 
(symbol-value ...))))) (let* ((last (last (symbol-value ...))) (base-size (cdr 
last)) (display-buffer-mark-dedicated (quote soft))) 
(with-output-to-temp-buffer "*Completions*" (if last (setcdr last nil)) (set 
(quote --cl-completions--) (sort (symbol-value ...) (quote string-lessp))) (if 
completion-annotate-function (set (quote --cl-completions--) (mapcar ... ...))) 
(save-current-buffer (set-buffer standard-output) (set (make-local-variable 
...) (list ... nil))) (display-completion-list (symbol-value (quote 
--cl-completions--))))) (minibuffer-hide-completions) (ding) 
(minibuffer-message (if (symbol-value (quote --cl-completions--)) "Sole 
completion" "No completions"))) nil))
  (let ((--cl-string-- (field-string))) (let ((--cl-completions-- 
(completion-all-completions (symbol-value (quote --cl-string--)) 
minibuffer-completion-table minibuffer-completion-predicate (- (point) 
(field-beginning))))) (progn (setq a (symbol-value (quote --cl-completions--))) 
(message nil) (if (and (symbol-value (quote --cl-completions--)) (or (consp 
(cdr ...)) (not (equal ... ...)))) (let* ((last (last ...)) (base-size (cdr 
last)) (display-buffer-mark-dedicated (quote soft))) 
(with-output-to-temp-buffer "*Completions*" (if last (setcdr last nil)) (set 
(quote --cl-completions--) (sort ... ...)) (if completion-annotate-function 
(set ... ...)) (save-current-buffer (set-buffer standard-output) (set ... ...)) 
(display-completion-list (symbol-value ...)))) (minibuffer-hide-completions) 
(ding) (minibuffer-message (if (symbol-value (quote --cl-completions--)) "Sole 
completion" "No completions"))) nil)))
  (let ((--cl-start-- (field-beginning))) (let ((--cl-string-- (field-string))) 
(let ((--cl-completions-- (completion-all-completions (symbol-value (quote 
--cl-string--)) minibuffer-completion-table minibuffer-completion-predicate (- 
(point) (field-beginning))))) (progn (setq a (symbol-value (quote 
--cl-completions--))) (message nil) (if (and (symbol-value (quote 
--cl-completions--)) (or (consp ...) (not ...))) (let* ((last ...) (base-size 
...) (display-buffer-mark-dedicated ...)) (with-output-to-temp-buffer 
"*Completions*" (if last ...) (set ... ...) (if completion-annotate-function 
...) (save-current-buffer ... ...) (display-completion-list ...))) 
(minibuffer-hide-completions) (ding) (minibuffer-message (if (symbol-value ...) 
"Sole completion" "No completions"))) nil))))
  (lexical-let ((start (field-beginning))) (lexical-let ((string 
(field-string))) (lexical-let ((completions (completion-all-completions string 
minibuffer-completion-table minibuffer-completion-predicate (- (point) 
(field-beginning))))) (setq a completions) (message nil) (if (and completions 
(or (consp (cdr completions)) (not (equal ... string)))) (let* ((last (last 
completions)) (base-size (cdr last)) (display-buffer-mark-dedicated (quote 
soft))) (with-output-to-temp-buffer "*Completions*" (when last (setcdr last 
nil)) (setq completions (sort completions ...)) (when 
completion-annotate-function (setq completions ...)) (with-current-buffer 
standard-output (set ... ...)) (display-completion-list completions))) 
(minibuffer-hide-completions) (ding) (minibuffer-message (if completions "Sole 
completion" "No completions"))) nil)))
  (lexical-let* ((start (field-beginning)) (string (field-string)) (completions 
(completion-all-completions string minibuffer-completion-table 
minibuffer-completion-predicate (- (point) (field-beginning))))) (setq a 
completions) (message nil) (if (and completions (or (consp (cdr completions)) 
(not (equal (car completions) string)))) (let* ((last (last completions)) 
(base-size (cdr last)) (display-buffer-mark-dedicated (quote soft))) 
(with-output-to-temp-buffer "*Completions*" (when last (setcdr last nil)) (setq 
completions (sort completions (quote string-lessp))) (when 
completion-annotate-function (setq completions (mapcar (lambda ... ...) 
completions))) (with-current-buffer standard-output (set (make-local-variable 
(quote completion-base-position)) (list (+ start base-size) nil))) 
(display-completion-list completions))) (minibuffer-hide-completions) (ding) 
(minibuffer-message (if completions "Sole completion" "No completions"))) nil)
  minibuffer-completion-help()
  (if (cond ((eql completion-auto-help (quote lazy)) (eq this-command 
last-command)) (t completion-auto-help)) (minibuffer-completion-help) 
(minibuffer-message "Next char not unique"))
  (cond ((and (not (condition-case nil (consp (nthcdr 
completion-cycle-threshold comps)) (error nil))) (consp (cdr comps))) (progn 
(set (quote --cl-completed--) t) (setq exact t)) (setq 
completion-all-sorted-completions comps) (minibuffer-force-complete)) 
((symbol-value (quote --cl-completed--)) (minibuffer-hide-completions)) ((not 
exact) (if (cond ((eql completion-auto-help (quote lazy)) (eq this-command 
last-command)) (t completion-auto-help)) (minibuffer-completion-help) 
(minibuffer-message "Next char not unique"))) ((eq this-command last-command) 
(if completion-auto-help (minibuffer-completion-help))))
  (let ((exact (test-completion (symbol-value (quote --cl-completion--)) 
minibuffer-completion-table minibuffer-completion-predicate)) (comps (if (and 
completion-cycle-threshold (or (not (symbol-value ...)) (< (car ...) 
(symbol-value ...)))) (completion-all-sorted-completions)))) (setq 
completion-all-sorted-completions nil) (cond ((and (not (condition-case nil 
(consp (nthcdr completion-cycle-threshold comps)) (error nil))) (consp (cdr 
comps))) (progn (set (quote --cl-completed--) t) (setq exact t)) (setq 
completion-all-sorted-completions comps) (minibuffer-force-complete)) 
((symbol-value (quote --cl-completed--)) (minibuffer-hide-completions)) ((not 
exact) (if (cond ((eql completion-auto-help (quote lazy)) (eq this-command 
last-command)) (t completion-auto-help)) (minibuffer-completion-help) 
(minibuffer-message "Next char not unique"))) ((eq this-command last-command) 
(if completion-auto-help (minibuffer-completion-help)))) (minibuffer--bitset 
(symbol-value (quote --cl-completed--)) t exact))
  (if (not (or (symbol-value (quote --cl-unchanged--)) (symbol-value (quote 
--cl-completed--)))) (completion--do-completion try-completion-function) (let 
((exact (test-completion (symbol-value (quote --cl-completion--)) 
minibuffer-completion-table minibuffer-completion-predicate)) (comps (if (and 
completion-cycle-threshold (or (not ...) (< ... ...))) 
(completion-all-sorted-completions)))) (setq completion-all-sorted-completions 
nil) (cond ((and (not (condition-case nil (consp ...) (error nil))) (consp (cdr 
comps))) (progn (set (quote --cl-completed--) t) (setq exact t)) (setq 
completion-all-sorted-completions comps) (minibuffer-force-complete)) 
((symbol-value (quote --cl-completed--)) (minibuffer-hide-completions)) ((not 
exact) (if (cond ((eql completion-auto-help ...) (eq this-command 
last-command)) (t completion-auto-help)) (minibuffer-completion-help) 
(minibuffer-message "Next char not unique"))) ((eq this-command last-command) 
(if completion-auto-help (minibuffer-completion-help)))) (minibuffer--bitset 
(symbol-value (quote --cl-completed--)) t exact)))
  (progn (if (symbol-value (quote --cl-unchanged--)) (goto-char (symbol-value 
(quote --cl-end--))) (completion--replace (symbol-value (quote --cl-beg--)) 
(symbol-value (quote --cl-end--)) (symbol-value (quote --cl-completion--)))) 
(forward-char (- (symbol-value (quote --cl-comp-pos--)) (length (symbol-value 
(quote --cl-completion--))))) (if (not (or (symbol-value (quote 
--cl-unchanged--)) (symbol-value (quote --cl-completed--)))) 
(completion--do-completion try-completion-function) (let ((exact 
(test-completion (symbol-value (quote --cl-completion--)) 
minibuffer-completion-table minibuffer-completion-predicate)) (comps (if (and 
completion-cycle-threshold (or ... ...)) (completion-all-sorted-completions)))) 
(setq completion-all-sorted-completions nil) (cond ((and (not (condition-case 
nil ... ...)) (consp (cdr comps))) (progn (set (quote --cl-completed--) t) 
(setq exact t)) (setq completion-all-sorted-completions comps) 
(minibuffer-force-complete)) ((symbol-value (quote --cl-completed--)) 
(minibuffer-hide-completions)) ((not exact) (if (cond (... ...) (t 
completion-auto-help)) (minibuffer-completion-help) (minibuffer-message "Next 
char not unique"))) ((eq this-command last-command) (if completion-auto-help 
(minibuffer-completion-help)))) (minibuffer--bitset (symbol-value (quote 
--cl-completed--)) t exact))))
  (let ((--cl-unchanged-- (eq t (compare-strings (symbol-value (quote 
--cl-completion--)) nil nil (symbol-value (quote --cl-string--)) nil nil 
nil)))) (progn (if (symbol-value (quote --cl-unchanged--)) (goto-char 
(symbol-value (quote --cl-end--))) (completion--replace (symbol-value (quote 
--cl-beg--)) (symbol-value (quote --cl-end--)) (symbol-value (quote 
--cl-completion--)))) (forward-char (- (symbol-value (quote --cl-comp-pos--)) 
(length (symbol-value (quote --cl-completion--))))) (if (not (or (symbol-value 
(quote --cl-unchanged--)) (symbol-value (quote --cl-completed--)))) 
(completion--do-completion try-completion-function) (let ((exact 
(test-completion (symbol-value ...) minibuffer-completion-table 
minibuffer-completion-predicate)) (comps (if (and completion-cycle-threshold 
...) (completion-all-sorted-completions)))) (setq 
completion-all-sorted-completions nil) (cond ((and (not ...) (consp ...)) 
(progn (set ... t) (setq exact t)) (setq completion-all-sorted-completions 
comps) (minibuffer-force-complete)) ((symbol-value (quote --cl-completed--)) 
(minibuffer-hide-completions)) ((not exact) (if (cond ... ...) 
(minibuffer-completion-help) (minibuffer-message "Next char not unique"))) ((eq 
this-command last-command) (if completion-auto-help 
(minibuffer-completion-help)))) (minibuffer--bitset (symbol-value (quote 
--cl-completed--)) t exact)))))
  (let ((--cl-completed-- (not (eq t (compare-strings (symbol-value (quote 
--cl-completion--)) nil nil (symbol-value (quote --cl-string--)) nil nil t))))) 
(let ((--cl-unchanged-- (eq t (compare-strings (symbol-value (quote 
--cl-completion--)) nil nil (symbol-value (quote --cl-string--)) nil nil 
nil)))) (progn (if (symbol-value (quote --cl-unchanged--)) (goto-char 
(symbol-value (quote --cl-end--))) (completion--replace (symbol-value (quote 
--cl-beg--)) (symbol-value (quote --cl-end--)) (symbol-value (quote 
--cl-completion--)))) (forward-char (- (symbol-value (quote --cl-comp-pos--)) 
(length (symbol-value (quote --cl-completion--))))) (if (not (or (symbol-value 
(quote --cl-unchanged--)) (symbol-value (quote --cl-completed--)))) 
(completion--do-completion try-completion-function) (let ((exact 
(test-completion ... minibuffer-completion-table 
minibuffer-completion-predicate)) (comps (if ... ...))) (setq 
completion-all-sorted-completions nil) (cond ((and ... ...) (progn ... ...) 
(setq completion-all-sorted-completions comps) (minibuffer-force-complete)) 
((symbol-value ...) (minibuffer-hide-completions)) ((not exact) (if ... ... 
...)) ((eq this-command last-command) (if completion-auto-help ...))) 
(minibuffer--bitset (symbol-value (quote --cl-completed--)) t exact))))))
  (let ((--cl-completion-- (car (symbol-value (quote --cl-comp--))))) (let 
((--cl-completed-- (not (eq t (compare-strings (symbol-value ...) nil nil 
(symbol-value ...) nil nil t))))) (let ((--cl-unchanged-- (eq t 
(compare-strings (symbol-value ...) nil nil (symbol-value ...) nil nil nil)))) 
(progn (if (symbol-value (quote --cl-unchanged--)) (goto-char (symbol-value 
(quote --cl-end--))) (completion--replace (symbol-value (quote --cl-beg--)) 
(symbol-value (quote --cl-end--)) (symbol-value (quote --cl-completion--)))) 
(forward-char (- (symbol-value (quote --cl-comp-pos--)) (length (symbol-value 
...)))) (if (not (or (symbol-value ...) (symbol-value ...))) 
(completion--do-completion try-completion-function) (let ((exact ...) (comps 
...)) (setq completion-all-sorted-completions nil) (cond (... ... ... ...) (... 
...) (... ...) (... ...)) (minibuffer--bitset (symbol-value ...) t exact)))))))
  (let ((--cl-comp-pos-- (cdr (symbol-value (quote --cl-comp--))))) (let 
((--cl-completion-- (car (symbol-value (quote --cl-comp--))))) (let 
((--cl-completed-- (not (eq t (compare-strings ... nil nil ... nil nil t))))) 
(let ((--cl-unchanged-- (eq t (compare-strings ... nil nil ... nil nil nil)))) 
(progn (if (symbol-value (quote --cl-unchanged--)) (goto-char (symbol-value 
...)) (completion--replace (symbol-value ...) (symbol-value ...) (symbol-value 
...))) (forward-char (- (symbol-value ...) (length ...))) (if (not (or ... 
...)) (completion--do-completion try-completion-function) (let (... ...) (setq 
completion-all-sorted-completions nil) (cond ... ... ... ...) 
(minibuffer--bitset ... t exact))))))))
  (cond ((null (symbol-value (quote --cl-comp--))) 
(minibuffer-hide-completions) (ding) (minibuffer-message "No match") 
(minibuffer--bitset nil nil nil)) ((eq t (symbol-value (quote --cl-comp--))) 
(minibuffer-hide-completions) (goto-char (field-end)) (minibuffer--bitset nil 
nil t)) (t (let ((--cl-comp-pos-- (cdr (symbol-value (quote --cl-comp--))))) 
(let ((--cl-completion-- (car (symbol-value ...)))) (let ((--cl-completed-- 
(not ...))) (let ((--cl-unchanged-- ...)) (progn (if ... ... ...) (forward-char 
...) (if ... ... ...))))))))
  (let ((--cl-comp-- (funcall (or try-completion-function (quote 
completion-try-completion)) (symbol-value (quote --cl-string--)) 
minibuffer-completion-table minibuffer-completion-predicate (- (point) 
(symbol-value (quote --cl-beg--)))))) (cond ((null (symbol-value (quote 
--cl-comp--))) (minibuffer-hide-completions) (ding) (minibuffer-message "No 
match") (minibuffer--bitset nil nil nil)) ((eq t (symbol-value (quote 
--cl-comp--))) (minibuffer-hide-completions) (goto-char (field-end)) 
(minibuffer--bitset nil nil t)) (t (let ((--cl-comp-pos-- (cdr (symbol-value 
...)))) (let ((--cl-completion-- (car ...))) (let ((--cl-completed-- ...)) (let 
(...) (progn ... ... ...))))))))
  (let ((--cl-string-- (buffer-substring (symbol-value (quote --cl-beg--)) 
(symbol-value (quote --cl-end--))))) (let ((--cl-comp-- (funcall (or 
try-completion-function (quote completion-try-completion)) (symbol-value (quote 
--cl-string--)) minibuffer-completion-table minibuffer-completion-predicate (- 
(point) (symbol-value (quote --cl-beg--)))))) (cond ((null (symbol-value (quote 
--cl-comp--))) (minibuffer-hide-completions) (ding) (minibuffer-message "No 
match") (minibuffer--bitset nil nil nil)) ((eq t (symbol-value (quote 
--cl-comp--))) (minibuffer-hide-completions) (goto-char (field-end)) 
(minibuffer--bitset nil nil t)) (t (let ((--cl-comp-pos-- (cdr ...))) (let 
((--cl-completion-- ...)) (let (...) (let ... ...))))))))
  (let ((--cl-end-- (field-end))) (let ((--cl-string-- (buffer-substring 
(symbol-value (quote --cl-beg--)) (symbol-value (quote --cl-end--))))) (let 
((--cl-comp-- (funcall (or try-completion-function (quote 
completion-try-completion)) (symbol-value (quote --cl-string--)) 
minibuffer-completion-table minibuffer-completion-predicate (- (point) 
(symbol-value ...))))) (cond ((null (symbol-value (quote --cl-comp--))) 
(minibuffer-hide-completions) (ding) (minibuffer-message "No match") 
(minibuffer--bitset nil nil nil)) ((eq t (symbol-value (quote --cl-comp--))) 
(minibuffer-hide-completions) (goto-char (field-end)) (minibuffer--bitset nil 
nil t)) (t (let ((--cl-comp-pos-- ...)) (let (...) (let ... ...))))))))
  (let ((--cl-beg-- (field-beginning))) (let ((--cl-end-- (field-end))) (let 
((--cl-string-- (buffer-substring (symbol-value (quote --cl-beg--)) 
(symbol-value (quote --cl-end--))))) (let ((--cl-comp-- (funcall (or 
try-completion-function ...) (symbol-value ...) minibuffer-completion-table 
minibuffer-completion-predicate (- ... ...)))) (cond ((null (symbol-value ...)) 
(minibuffer-hide-completions) (ding) (minibuffer-message "No match") 
(minibuffer--bitset nil nil nil)) ((eq t (symbol-value ...)) 
(minibuffer-hide-completions) (goto-char (field-end)) (minibuffer--bitset nil 
nil t)) (t (let (...) (let ... ...))))))))
  (lexical-let ((beg (field-beginning))) (lexical-let ((end (field-end))) 
(lexical-let ((string (buffer-substring beg end))) (lexical-let ((comp (funcall 
(or try-completion-function ...) string minibuffer-completion-table 
minibuffer-completion-predicate (- ... beg)))) (cond ((null comp) 
(minibuffer-hide-completions) (ding) (minibuffer-message "No match") 
(minibuffer--bitset nil nil nil)) ((eq t comp) (minibuffer-hide-completions) 
(goto-char (field-end)) (minibuffer--bitset nil nil t)) (t (lexical-let* (... 
... ... ...) (if unchanged ... ...) (forward-char ...) (if ... ... ...))))))))
  (lexical-let* ((beg (field-beginning)) (end (field-end)) (string 
(buffer-substring beg end)) (comp (funcall (or try-completion-function (quote 
completion-try-completion)) string minibuffer-completion-table 
minibuffer-completion-predicate (- (point) beg)))) (cond ((null comp) 
(minibuffer-hide-completions) (ding) (minibuffer-message "No match") 
(minibuffer--bitset nil nil nil)) ((eq t comp) (minibuffer-hide-completions) 
(goto-char (field-end)) (minibuffer--bitset nil nil t)) (t (lexical-let* 
((comp-pos (cdr comp)) (completion (car comp)) (completed (not (eq t ...))) 
(unchanged (eq t (compare-strings completion nil nil string nil nil nil)))) (if 
unchanged (goto-char end) (completion--replace beg end completion)) 
(forward-char (- comp-pos (length completion))) (if (not (or unchanged 
completed)) (completion--do-completion try-completion-function) (let ((exact 
...) (comps ...)) (setq completion-all-sorted-completions nil) (cond (... ... 
... ...) (completed ...) (... ...) (... ...)) (minibuffer--bitset completed t 
exact)))))))
  completion--do-completion()
  (let ((--cl-var-- (completion--do-completion))) (cond ((eql --cl-var-- (quote 
0)) nil) ((eql --cl-var-- (quote 1)) (minibuffer-message "Sole completion") t) 
((eql --cl-var-- (quote 3)) (minibuffer-message "Complete, but not unique") t) 
(t t)))
  (case (completion--do-completion) (0 nil) (1 (minibuffer-message "Sole 
completion") t) (3 (minibuffer-message "Complete, but not unique") t) (t t))
  (cond ((window-live-p minibuffer-scroll-window) (let ((window 
minibuffer-scroll-window)) (with-current-buffer (window-buffer window) (if 
(pos-visible-in-window-p (point-max) window) (set-window-start window 
(point-min) nil) (scroll-other-window)) nil))) 
(completion-all-sorted-completions (minibuffer-force-complete) t) (t (case 
(completion--do-completion) (0 nil) (1 (minibuffer-message "Sole completion") 
t) (3 (minibuffer-message "Complete, but not unique") t) (t t))))
  minibuffer-complete()
  call-interactively(minibuffer-complete nil nil)
  completing-read("Describe function (default try-completion): " 
[edebug-toggle-save-selected-window edebug-install-read-eval-functions 
retrieve-tag inhibit-debug-on-entry edebug-stack cl-setf-do-store 
widget-field-end widget-princ-to-string x-select-enable-primary 
change-log-search-tag-name change-log-mode-abbrev-table xlfd-tight-regexp 
log-buf file-name-shadow-tty-properties cl-declarations-or-string cl-type-spec 
font-lock-regexp-grouping-backslash rmail-primary-inbox-list model name-props 
diff-find-source-location change-log-start-entry-re Set\ Conditional\ 
Breakpoint extra-name file-or-dir-list vc-sentinel-movepoint add-log-file-name 
widget-default-get global-edebug-prefix loop-clause 
menu-bar-showhide-fringe-ind-mixed :button-face widget-link-prefix 
change-log-function noreuse edebug-outside-buffer 
vc-annotate-parent-display-mode edebug-where cl-maphash tree-equal 
create-fontset-from-ascii-font help-package whitespace-insert-value 
widget-editable-list-insert-before Previous\ Topic Go-nonstop convert-widget 
Eval edebug-trace cdaar ...] fboundp t nil nil "try-completion")
  (setq val (completing-read (if fn (format "Describe function (default %s): " 
fn) "Describe function: ") obarray (quote fboundp) t nil nil (and fn 
(symbol-name fn))))
  (let ((fn (function-called-at-point)) (enable-recursive-minibuffers t) val) 
(setq val (completing-read (if fn (format "Describe function (default %s): " 
fn) "Describe function: ") obarray (quote fboundp) t nil nil (and fn 
(symbol-name fn)))) (list (if (equal val "") fn (intern val))))
  call-interactively(describe-function nil nil)

The list apparently being completed is this:

(#("pop-to-mark-command" 0 4 (font-lock-face completions-common-part) 4 5 
(font-lock-face completions-first-difference)) #("pop-tag-mark" 0 4 
(font-lock-face completions-common-part) 4 5 (font-lock-face 
completions-first-difference)) #("pop-global-mark" 0 4 (font-lock-face 
completions-common-part) 4 5 (font-lock-face completions-first-difference)) 
#("pop-to-buffer" 0 4 (font-lock-face completions-common-part) 4 5 
(font-lock-face completions-first-difference)) #("pop-mark" 0 4 (font-lock-face 
completions-common-part) 4 5 (font-lock-face completions-first-difference)) . 0)

  
  
-- 
(domestic pets only, the antidote for overdose, milk.)
  address@hidden * Lars Magne Ingebrigtsen