list-load-path-shadows misses results

[D. Goel]

Suppose you have modified simple.el and store a copy of it in the
local directory.  Or suppose you were not aware that emacs comes with
a simple.el, and you are playing around with your own example-file
simple.el.  As soon as you do that, M-x list-load-path-shadows becomes
unreliable, for instance:

  (start an emacs -q -no-site-file).  Then

,----
| $ cp /usr/local/gnu/share/emacs/21.1/lisp/indent.el ~/emacs/
| (add-to-list 'load-path "~/emacs")
| M-x list-load-path-shadows
|  
|  will show indent.el shadowing. Now, 
| 
| 
| $ cp /usr/local/gnu/share/emacs/21.1/lisp/simple.el ~/
| (add-to-list 'load-path "~/")
| M-x list-load-path-shadows
|   
|  will stop showing the indent.el shadowing. 
`----


(A noninteractive function: (find-emacs-lisp-shadows) will continue to
find all the shadows, the problem is that list-load-path-shadows
prunes the load-path before calling that function..)

The behavior above happens because M-x list-load-path-shadows tries to
be smart about eliminating some 'false positives' on some machines,
which may have a "source" directory and an "installed" directory, and
hence multiple simple.el's...

IMHO, these false positives seldom would occur anyways.  And getting
false positives is not so bad as missing true positives.  Imagine a
newbie creating a test-file "simple.el" and suddenly no shadows are
listed, esp. the most important--simple.el.

Perhaps list-load-path-shadows could make this optional---stop doing
this load-path-pruning, unless a particular option is set.

i would be glad to submit a patch if folks like the proposed
behavior.  (this is the same function, for which i have proposed to
work on making the results 'clickabke' in another email.)


In GNU Emacs 21.1.3 (alphaev56-dec-osf4.0f, X toolkit, Xaw3d scroll bars)
 of 2001-10-30 on shorty.csc.umd.edu
configured using `configure  --prefix=/usr/local/gnu 
--infodir=/usr/local/gnu/info/emacs-21.1 --with-kerberos --with-x 
--with-x-toolkit=yes --with-xpm --with-jpeg --with-tiff --with-gif --with-png'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: nil
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug: