bug#59874: Segfault from string-ref with negative 'k'

[rose gibson]

hi,

i noticed that if i, on my system, run "guile" from a shell and then type into 
the command prompt that appears,

(string-ref "a string" -1)

guile appears to hang for a few seconds or so, and then prints the message 
"Segmentation fault (core dumped)".

i'm not really sure if this report is worth anything, it might just be some 
glitch in my distribution's build or something else unreproducable and weird, 
idk.  but i thought i would say something.  just in case.

this is with guile 3.0.8 on arch linux.  i didn't do anything special with 
respect to building guile myself or anything like that, it was (i'm pretty 
sure) just installed from the repositories.

i'm definitely curious what's up if anyone ever bothers to take the time 
figuring it out.

thanks :)