Re: Incorrect byte compiler error/warning message positions. A possible fix.

[Stefan Monnier]

>> In my experience, the vast majority of the warning messages point to the
>> correct position.  But, yes, it does sometimes give the wrong position.
> On 2018-11-22 (before you destroyed my test dataset by fixing all the
> warnings in Emacs ;-) there were 335 warnings.  81 gave the correct
> location, 254 a wrong one.

FWIW, I think the current code gives (statistically) slightly less bad
positions, because of changes I've made to `cconv` and `bytecomp`.
That may explain Lars's impression.

Our positions are still too often poor.  Some of us have just grown used
to missing or poor location info and don't notice them any more :-(

> They should be fairly easy (if, perhaps, tedious) to solve, because
> everything is under our control.

Agreed.

> It's macros where people outside of our control do wierd and wonderful
> things.  I think I know how to compile macros so that they both work,
> yet preserve the symbols with position on the code they generate.
> These compiled macros won't work on earlier versions of Emacs, but
> that's a bridge to cross when we come to it.

I'm curious know how you intend to make it work,


        Stefan