bug#23833: 24.5; assoc-string with CASE-FOLD may fail

[ynyaaa@gmail.com]

`assoc-string' called with non-nil CASE-FOLD argument may fail to match
with downcased key.

(let (l)
  (dotimes (c (max-char))
    (or (let ((s (string c)))
          (assoc-string (downcase s) (list s) t))
        (setq l (cons c l))))
  l)
=>(497 458 455 452)



In GNU Emacs 24.5.1 (i686-pc-mingw32)
 of 2015-04-11 on LEG570
Windowing system distributor `Microsoft Corp.', version 6.0.6002
Configured using:
 `configure --prefix=/c/usr --host=i686-pc-mingw32'

Important settings:
  value of $LANG: JPN
  locale-coding-system: cp932

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:

Quit
C-h C-b is undefined

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils advice help-fns time-date japan-util
tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
dos-w32 ls-lisp w32-common-fns disp-table w32-win w32-vars tool-bar dnd
fontset image regexp-opt fringe tabulated-list newcomment lisp-mode
prog-mode register page menu-bar rfn-eshadow timer select scroll-bar
mouse jit-lock font-lock syntax facemenu font-core frame cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
w32notify w32 multi-tty emacs)

Memory information:
((conses 8 76911 6828)
 (symbols 32 17601 0)
 (miscs 32 34 127)
 (strings 16 11124 3996)
 (string-bytes 1 279109)
 (vectors 8 10463)
 (vector-slots 4 464483 4962)
 (floats 8 57 134)
 (intervals 28 185 22)
 (buffers 508 12))