bug#15713: 24.3.50; wrong-type-argument char-table-p when visiting C++ file

[Claudio Bley <claudio.bley@googlemail.com>]

1. run "emacs -Q".
2. C-x C-f test.cpp RET

Debugger entered--Lisp error: (wrong-type-argument char-table-p nil)
  char-table-parent(nil)
  c++-mode()
  set-auto-mode-0(c++-mode nil)
  set-auto-mode()
  normal-mode(t)
  after-find-file(nil t)
  find-file-noselect-1(#<buffer test.cpp> "x:/src/test.cpp" nil nil "x:/src/test.cpp" ((1536 7 . 46561) (16106 . 22486)))
  find-file-noselect("x:/src/test.cpp" nil nil t)
  find-file("x:/src/test.cpp" t)
  call-interactively(find-file nil nil)
  command-execute(find-file)


In GNU Emacs 24.3.50.11 (i686-pc-mingw32)
 of 2013-10-22 on CLAUDIO-PC
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/emacs24.3
 CPPFLAGS=-I/c/Users/Claudio/src/emacs-dep/stage/include
 'LDFLAGS=-shared-libgcc -L/c/Users/Claudio/src/emacs-dep/stage/lib''

Important settings:
  value of $LANG: DEU
  locale-coding-system: cp1252
  default enable-multibyte-characters: t

Major mode: Debugger

Minor modes in effect:
  tooltip-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
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-x C-f <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> x : / s r <tab> 
t <tab> . <tab> c <tab> <return> <help-echo> 
M-x r e p o <tab> r t - <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Debug on Error enabled globally
Making completion list... [2 times]
File mode specification error: (wrong-type-argument char-table-p nil)
Entering debugger...
Making completion list...

Load-path shadows:
None found.

Features:
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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 debug cus-start cus-load vc-hg cc-mode cc-fonts
cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs
help-mode easymenu time-date tooltip 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
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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)