compiler warnings for "unused" method specializers

[Eric Abrahamsen]

I'm having to go through a whole bunch of code and add leading
underscores to method parameters used as specializers, to quiet the
compiler. I guess this makes sense, in a way -- the parameters aren't
actually used in the function body -- but doesn't make sense in another
way: the parameters are essential to determining how and when this
method is run. So I need to do:

(cl-defmethod foo ((thing my-object) (_style (eql disco)))
  (message "%s points at the ceiling" thing))

There might be better solutions for this stupid example, but I have many
cases where it's pretty much necessary to specialize on a parameter that
isn't actually used.

My other instinct was to just put "_" for all unused parameters, but if
there's more than one of those, the compiler complains about repeated
variables.

Could the compiler special-case this situation somehow (either not
complaining about unused variables, or not complaining about repeated
variables)? Or am I just being overly persnickety about this?

Eric