Re: feature/native-comp c60f2f4: Fix `comp-cstr-intersection-no-hashcons' for negated result cstr

[Andrea Corallo via "Emacs development discussions." <emacs-devel@gnu.org>]

Pip Cet <pipcet@gmail.com> writes:

> On Sat, Mar 6, 2021 at 10:17 PM Andrea Corallo <akrl@savannah.gnu.org> wrote:
>> branch: feature/native-comp
>> commit c60f2f458a63a8ae4288652228f24e43fdc7bba7
>> Author: Andrea Corallo <akrl@sdf.org>
>> Commit: Andrea Corallo <akrl@sdf.org>
>>
>>     Fix `comp-cstr-intersection-no-hashcons' for negated result cstr
>>
>>         * lisp/emacs-lisp/comp-cstr.el
>>         (comp-cstr-intersection-no-hashcons): When negated and
>>         necessary relax dst to t.
>>         * test/src/comp-tests.el (comp-tests-type-spec-tests): Add a test.
>> ---
>>  lisp/emacs-lisp/comp-cstr.el | 32 +++++++++++++++++++-------------
>>  test/src/comp-tests.el       |  9 ++++++++-
>>  2 files changed, 27 insertions(+), 14 deletions(-)
>>
>> diff --git a/lisp/emacs-lisp/comp-cstr.el b/lisp/emacs-lisp/comp-cstr.el
>> index d6423ef..4397a91 100644
>> --- a/lisp/emacs-lisp/comp-cstr.el
>> +++ b/lisp/emacs-lisp/comp-cstr.el
>> @@ -1001,20 +1001,26 @@ promoted to their types.
>>  DST is returned."
>>    (with-comp-cstr-accessors
>>      (apply #'comp-cstr-intersection dst srcs)
>
> I still think this code is incorrect, because it does an eq/eql-based
> intersection first and tries to relax the constraint later. Consider
>
> (let ((comp-ctxt (make-comp-cstr-ctxt)))
>   (comp-cstr-intersection-no-hashcons
>    (make-comp-cstr)
>    (comp-value-to-cstr '(a))
>    (comp-value-to-cstr '(a))))
>
> That should return a constraint matching all (or many) conses, right?
> It returns an empty constraint.

I think you are right, will have a look into this evening.

Thanks

  Andrea