On Thu, Mar 14, 2024 at 5:05 AM Eli Zaretskii <eliz@gnu.org> wrote:

> > +(defcustom flymake-margin-indicators-string
> > +  `((error ,(if (char-displayable-p 8252)
> > +               "‼"
> > +             "!!")
> > +     compilation-error)
>
> When do you expect this value to be evaluated?
>
> In general, I wonder whether it would be simpler and wiser to use just
> "!!", and leave it to users to customize to "‼" if their displays
> support that.  (We can mention the possibility in the doc string.)

I implemented it in a similar way to how display-fill-column-indicator
does with display-fill-column-indicator-character, this since I expect
users to only set left-margin-width to 1, because if there is several
errors on the same line, the indicators will be displayed next to each
other and it could be confusing.

However I agree that it is better to change it to just "!!",
I fixed the patch and added a doc string for the possibility of including
non-ASCII characters.