Re: Thoughts on getting correct line numbers in the byte compiler's warning messages

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> Changing `eq` would better be avoided,
> I agree, but don't see how we can avoid it.

Oh... you mean when someone else's macro does for example

   (defmacro ...
     (if (eq x 'foo)
         `(...)
       `(...)))

...hmm... yes, this is getting really ugly.

Maybe the "big cons-cells" approach is not that bad after all, since it
doesn't try to introduce new objects which are "equal but not": it just
introduces a subtype of cons-cells and that's that, so it's semantically
much simpler/cleaner.

It will require special code in alloc.c to keep the special
representation of normal cons-cells, and special extra code to propagate
the location information in macroexp.el, cconv.el, byte-opt.el,
bytecomp.el but the impact should be much more localized (and at places
where normal compilers also have to do this kind of work).


        Stefan