Subject: bug#67568: Emacs master: Bug in byte compiler when there's an unused parameter.

From: Dmitry Gutov <[email-masked]>
Date: Fri, 1 Dec 2023 15:06:23 +0200

On 01/12/2023 14:49, Alan Mackenzie wrote:
> On a recent Emacs master:
> 
> (i) emacs -Q
> (ii) In*scratch*  enter the following:
> 
>      (byte-compile (lambda (x) "doc" "foo"))
> 
>    .
> (iii) Enter C-u C-x C-e to evaluate the form.  The result looks like:
> 
>      #[257 "\300\207" [nil] 2 "doc
> 
>      (fn X)"]
> 
>    .  This is incorrect.  The only form in the constants vector is nil.
>    It should be "foo".
> 
> (iv) Note that this only happens with the unused parameter x.  Without
> it, the form compiles correctly.

Might be a bug in the interpreter too?

(funcall (lambda (x) "doc" "foo") 2)

;; => nil