Re: Help please! To track down GC trying to free an already freed object.

[Alex <agrambot@gmail.com>]

Alan Mackenzie <acm@muc.de> writes:

> Hello again, Daniel.
>
> On Tue, Apr 02, 2019 at 13:33:02 -0700, Daniel Colascione wrote:
>
>> So if I read symbol foo from file1.el and symbol foo from file2.el, I get
>> two different symbol-with-location instances, each tagged with a different
>> source location? Do these symbol objects compare eq to each other?
>
> They do, yes.  Otherwise the byte compiler wouldn't work, as it
> frequently compares a symbol-with-position with a constant ("ordinary")
> symbol using eq.
>
> However, it is envisaged the flag symbols-with-pos-enable will be bound
> to non-nil only by the byte compiler.  The reader resets this position to
> zero for each top-level form it reads.

I apologize if this topic already reached its conclusion, but IMO
having eq return true for two different object types is quite
surprising behaviour. Is it out of the question to leave eq alone and
introduce, e.g., eq-excluding-position that strips possible positions
before comparison?