Why can't local-set-key (kbd "n") in diff-mode ?

[boyang]

Hi 


Greetings,
I'm a Emacs newbie, when I do the following:
----------------------------------------------------------------------------------------
(add-hook 'diff-mode-hook
                   (lambda ()
                      (local-set-key (kbd "n") 'next-error-no-select)
                      (local-set-key (kbd "p") 'previous-error-no-select)))
----------------------------------------------------------------------------------------

It doesn't work, when I press "n" in "*Diff*", it stills run "diff-hunk-next"
when I "C-h k n", it still shows "diff-hunk-next".  Same also for "p".


But 
1. If I do the same thing in other mode, say "occur-mode-hook", it works in 
that mode.
2. If I set other key other than "n" in "diff-mode-hook", say "x", it works.


So is there somebody can tell me the reason behind this ?


Thank you


Cheers,
Boyang