On 10/9/23 11:24, Stefan Kangas wrote:
 >> I worked on something like that for elint.el, based on the wishlist on
 >> Bug#2591: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=2591
 >>
 >> But I know it might be better to make it so that the byte-compiler
 >> warns, so I never posted it.
 >
 > I'm not sure if elint.el is used all that much, but I might be wrong.

A shame, if you ask me.  It helped me find two more options with this
problem: font-lock-verbose and message-openpgp-header.  I attach an
updated patch, but let me know if you prefer a separate bug report.