bug#6843: grep-mode and filenames with colons

[npostavs]

Dmitry Gutov <dgutov@yandex.ru> writes:

> I'd prefer to have either grep-with-null-regexp-alist and
> grep-[without-null-]-regexp-alist, or grep-regexp-alist and
> grep-fallback-regexp-alist. Just a suggestion.
>

[...]

>>
>>> If the numbers are the same, we could keep the variable's name the same as
>>> well. As a result, most third-party code would continue to simply work.
>>
>> Might be worth using explicitly numbered groups to keep the numbers for
>> FILE and COLUMN the same though.
>
> Yes, I think it will be a good idea. Provided we can combine it with
> renaming either of the variables back to grep-regexp-alist. Otherwise,
> any backward compatibility is broken anyway.

That part is already covered by this, no?

    (defvaralias 'grep-regex-alist 'grep-with-null-regexp-alist)
    (make-obsolete-variable
     'grep-regex-alist "Call `grep-regexp-alist' instead." "26.1")