Let cant-next-line.el have file contents:

  (tool-bar-mode 0)
  (global-whitespace-mode 1)
  (set-face-attribute 'default nil :height 80)
  (setq scroll-margin 4)
  (setq scroll-conservatively 101)

Open up the attached cant-next-line.txt by:

  emacs -Q --load cant-next-line.el cant-next-line.txt

Move point to be immediately before the 'h' of "here". Try to reach the '-'
character at the end of the file using C-n. You can't. If I move point to
the beginning of line containing "here", then I can.

I checked emacs-24.3 and could not reproduce this, so it is a regression.

I witnessed this with latest trunk 68068a328a854998a0071f4714cbacdfed36fcc1
and for commit 20899d085afe62520113b5acbfe3dbba57823dc9 (Jun 5) which I use
day to day (because the commit immediately following broke Evil in a
critical way).

---

In GNU Emacs 24.3.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.10.4)
 of 2013-06-18 on psd15
Windowing system distributor `The X.Org Foundation', version 11.0.70101000
System Description:    Red Hat Enterprise Linux Client release 5.4 (Tikanga)

Configured using:
 `configure
 --prefix=/redacted/user/boreilly/sw/emacs-install-trunk-20899d085afe62520113b5acbfe3dbba57823dc9
 --with-gif=no'

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Text

Minor modes in effect:
  global-whitespace-mode: t
  tooltip-mode: t
  mouse-wheel-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 input:
M-x r e p o r t <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
(shadow sort nadvice 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 disp-table whitespace time-date
tooltip ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar
dnd fontset image regexp-opt fringe tabulated-list newcomment lisp-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 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 dbusbind
dynamic-setting system-font-setting font-render-setting move-toolbar gtk
x-toolkit x multi-tty emacs)