GNU bug report logs - #25166
It shouldn't be possible to set the function cell of t

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Package: emacs;

Reported by: Philipp <p.stephani2 <at> gmail.com>

Date: Sun, 11 Dec 2016 09:47:02 UTC

Severity: wishlist

Tags: wontfix

Found in version 26.0.50

Done: Noam Postavsky <npostavs <at> users.sourceforge.net>

Bug is archived. No further changes may be made.

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From: Glenn Morris <rgm <at> gnu.org>
To: Philipp <p.stephani2 <at> gmail.com>
Cc: 25166 <at> debbugs.gnu.org
Subject: bug#25166: 26.0.50; It shouldn't be possible to set the function cell of nil and t
Date: Sun, 11 Dec 2016 13:38:57 -0500

Philipp wrote:

> You can set the function cell of nil and t using `fset' and friends.
> But you can't call the `nil' function using (nil) (it does work with
> (t)).  I think that attempting to set the function cell of nil and t is
> almost always a bug -- probably the programmer wanted to set a real
> symbol, but some of the constants got passed.  I propose to signal an
> error (e.g. `setting-constant') whenever the function cell of nil and t
> is modified; maybe the same should happen for keywords.

I just did this yesterday...
See https://debbugs.gnu.org/25110, ba8e883, and 3fd4433.
This bug report was last modified 7 years and 267 days ago.

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