`list-load-path-shadows' ignores more directories than it should

[Michael Ernst]

In Emacs 21.2, list-load-path-shadows cuts off the search at the second
directory containing "simple.el".  I believe it should cut off at the last
directory containing "simple.el", the better to detect conflicts arising
from having multiple versions of lisp/ (for instance, from two different
Emacs installations) in one's path.  The below path accomplishes this.
Alternately, one could check that all versions of simple.el that are being
cut off are identical.

ChangeLog entry:

2002-03-25  Michael Ernst  <mernst@alum.mit.edu>

        * emacs-lisp/shadow.el (list-load-path-shadows): Only ignore last
        copy of "simple.el", etc.


*** /g2/users/mernst/tmp/emacs-21.2/lisp/emacs-lisp/shadow.el   Mon Jul 16 
08:22:59 2001
--- -   Sat Mar 23 21:41:02 2002
***************
*** 215,222 ****
      (if (> (length toplevs) 1)
        ;; Cut off our copy of load-path right before
!       ;; the second directory which has simple.el in it.
        ;; This avoids loads of duplications between the source dir
        ;; and the dir where these files were copied by installation.
!       (let ((break (nth (- (length toplevs) 2) toplevs)))
          (setq tem path)
          (while tem
--- 215,222 ----
      (if (> (length toplevs) 1)
        ;; Cut off our copy of load-path right before
!       ;; the last directory that has simple.el in it.
        ;; This avoids loads of duplications between the source dir
        ;; and the dir where these files were copied by installation.
!       (let ((break (car toplevs)))
          (setq tem path)
          (while tem