Re: Correct byte compiler error/warning positions. The solution!

[Alan Mackenzie <acm@muc.de>]

Hello, Lars.

On Wed, Dec 01, 2021 at 18:04:54 +0100, Lars Ingebrigtsen wrote:
> Alan Mackenzie <acm@muc.de> writes:

> > I would like to merge this branch, when it becomes stable, into master,
> > thus finally resolving the bug of the wrong positions in warning
> > messages from the byte compiler.

> > Comments would be welcome.

> Would this mean that other parts of the byte compilation machinery would
> need to be changed, since two symbols read while doing that won't be
> `eq' any more?

The branch is working code, capable of bootstrapping Emacs, at least in
a non-native-code configuration.

lisp_h_EQ (in lisp.h) has been modified such that #<symbol foo at 100>
is `eq' #<symbol foo at 200>.

The compilation machinery is basically unchanged.

> Does the positions leak out from the symbols anywhere else, like when
> doing reads outside the byte compilation process?

`read' is as it always was.  There is a new function
`read-positioning-symbols' which returns symbols (apart from nil) as
symbols-with-position.  It is called only from the byte compiler.

Any such leakages are bugs to fix.  This we can do.

> -- 
> (domestic pets only, the antidote for overdose, milk.)
>    bloggy blog: http://lars.ingebrigtsen.no

-- 
Alan Mackenzie (Nuremberg, Germany).