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

[Alan Mackenzie]

Hello, Eli.

On Sat, Nov 27, 2021 at 12:07:10 +0200, Eli Zaretskii wrote:
> > Date: Sat, 27 Nov 2021 09:31:05 +0000
> > Cc: emacs-devel@gnu.org
> > From: Alan Mackenzie <acm@muc.de>

> > Hello, Eli.

> > On Sat, Nov 27, 2021 at 07:53:36 +0200, Eli Zaretskii wrote:
> > > > Date: Fri, 26 Nov 2021 19:56:21 +0000
> > > > From: Alan Mackenzie <acm@muc.de>

> > > > A _LOT_ of these comparisons were for NILP, which is just #defined as EQ
> > > > (arg, Qnil).  However if NILP were to be defined directly as arg ==
> > > > Qnil, it would bypass the overhead in EQ.

> > > How can you use == when the operands could be structures?

> > I meant that NILP will be implemented as a binary comparison against
> > zero, omitting the awkward test for symbols_with_position_enabled.

> Please don't write code that assumes Qnil is zero.  (Or maybe I still
> misunderstand what exactly you mean by the above.)

Don't worry!  The new code merely assumes Qnil is a symbol, and leaves it
to the compiler to optimise for Qnil being binary zero.

-- 
Alan Mackenzie (Nuremberg, Germany).