I apologize if I'm misunderstanding things.  I'm certainly not
suggesting removing any functionality that is useful on old monochrome
ttys.  The reason I became aware of this bug is that I am using a
monochrome tty.

> > Still, this anachronistic kludge should really be nuked entirely.

> Why?  And what's "anachronistic" about that code?

What's anachronistic about that code (meaning the
ispell-highlight-spelling-error-generic function) is that it uses a
kludge that made it possible in pre-version-21 emacs to get some text
displayed in inverse video on a tty even though emacs could not
display faces on ttys.  But since Emacs 21, on any tty that has a
termcap "so" capability, you can get inverse-video simply by using an
inverse-video face.

So I don't think ispell-highlight-spelling-error-generic currently
provides any functionality that isn't more conveniently and
maintainably provided by ispell-highlight-spelling-error-overlay, with
the additional benefit that the user can, if he wants, customize
ispell-highlight-face to something other than inverse-video.

(Making the default isearch face (and therefore the default
ispell-highlight-face) be blue-on-magenta on color terminals but
inverse-video on monochrome terminals is already handled
automatically.)