bug#64402: Byte compile bug in calfw

[Sylvain Salvati]

Hello,

I have tried to re-use the package calfw (https://melpa.org/#/calfw)
that I had not used in a while.

Sadly, it did not work and the backtrace looked rather strange. After a
while I have been comparing the bytecode of the faulty function that I
have with my present version of emacs :

GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.20, cairo 
version 1.16.0) 

to the one that was compiled with emacs 28.2 which was working when I
was using it.


Emacs 30.0.50 bytecode

(defalias 'cfw:dest-ol-selection-clear #[(dest) "\304!\305     :\203  
@\306\n!\210    A\211\202*\307!\310\305\311#)\207" [dest #1=#:--cl-var-- i 
#2=#:v #[(cl-x) "\301!\204\302\303\304D\"\210\305H\207" [cl-x #[(cl-x) 
"\302!        >\205   \303\207" [cl-x cl-struct-cfw:dest-tags type-of t] 2] 
signal wrong-type-argument cfw:dest 10] 4] nil delete-overlay #[(cl-x) 
"\301!\204\302\303\304D\"\210\305H\207" [cl-x #[(cl-x) "\302! >\205   
\303\207" [cl-x cl-struct-cfw:dest-tags type-of t] 2] signal 
wrong-type-argument cfw:dest 10] 4] \(setf\ 
internal--with-suppressed-warnings\) ((lexical cl-x))] 5 (#$ . 69087)])

Emacs 28.2 bytecode

(defalias 'cfw:dest-ol-selection-clear #[(dest) "\305! 
>\204\306\307\310D\"\210\311H\312\n:\203(\n@\313!\210\nA\211\202*\305!    
>\2048\306\307\310D\"\210\211\311\312I)\207" [dest cl-struct-cfw:dest-tags 
#1=#:--cl-var-- i #2=#:v type-of signal wrong-type-argument cfw:dest 10 nil 
delete-overlay] 5 (#$ . 60812)])

The error raised in the backtrace in emacs 30 is produced by the
function call :

\(setf\ internal--with-suppressed-warnings\) ((lexical cl-x))

It seems that the problem is actually coming from the byte compiler.
Maybe calfw is using a particular combination of features that stumbles
on this problem.

Best,

S.