bug#45610: 27.1; Symbol’s function definition is void: seq-concatenate

[Eli Zaretskii]

> From:  Leo Liu <sdl.web@gmail.com>
> Cc: 45610@debbugs.gnu.org
> Date: Sun, 03 Jan 2021 00:07:47 +0800
> 
> On 2021-01-02 16:25 +0200, Eli Zaretskii wrote:
> > Thanks.  Then does the patch below fix the problem in Emacs 27.1?
> 
> Yes it does.

Then I'd like to push this fix to the release branch, but...

> >  (defun cl-concatenate (type &rest sequences)
> >    "Concatenate, into a sequence of type TYPE, the argument SEQUENCEs.
> >  \n(fn TYPE SEQUENCE...)"
> > +  (require 'seq)
> >    (apply #'seq-concatenate type sequences))
> >  
> >  ;;; List functions.
> 
> But it seems the function will become slower when called regularly
> because of the (require 'seq).

...slightly, yes.

> Is it better to remove cl-concatenate from the cl-proclaim list in
> cl-macs.el?

Wouldn't that make it even slower?  And cause incompatibilities with
already byte-compiled files that saw the original cl-macs.el?

But I'm not an expert on these issues, so I'l defer to Stefan and Lars
here.