bug#33314: 27.0.50; wrong compiler warning

["Andreas Röhler" <andreas.roehler@online.de>]

On 08.11.2018 16:54, Alan Mackenzie wrote:
> Hello, Andreas.
> 
> In article <mailman.3649.1541688141.1284.bug-gnu-emacs@gnu.org> you wrote:
>> Get a compiler Warning: Unused lexical variable ‘regexp’
> 
>> WRT a form like below:
>
> Reformatting that to make things clearer:
> 
> (defun foo (regexp &optional something)
>    "..."
>    (unless (bobp)
>      (when (empty-line-p) (skip-chars-backward " \t\r\n\f"))
>      (let* ((orig (point))
>             (regexpvalue
>              (if (eq regexp 'py-clause-re)
>                  (symbol-value 'py-extended-block-or-clause-re)
>                (symbol-value regexp)))
> 
>> ;;
> 
>> As visible, regexp is evaluated in last clause.
> 
> Does the rest of that let* form use regexpvalue?  If not, the lack of
> use of regexpvalue will, I believe, transfer to regexp.
> 
> Incidentally, why write (symbol-value 'py-extended-block-or-clause-re)
> rather than just py-extended-block-or-clause-re?
> 

Hi Alan,

that form is used to make a decision at a certain point:

(cond ((and
		     (member
		      regexp
		      (list
		       'py-block-or-clause-re
		   ...
		       ))
		     (looking-at regexpvalue))

So regexpvalue is used too. May send the complete function if interested.