Re: pcase map binding form expansion failure on Emacs 27 only

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

Adam Porter <adam@alphapapa.net> writes:

> So there seems to be a discrepancy between the version of the library
> returned by `locate-library' and the version of the activated package,
> and the version *actually* loaded into Emacs.  Installing newer versions
> of core libraries from ELPA doesn't seem to work, or at least not
> reliably, on Emacs 27.  But on Emacs 26.3 and Emacs 28.0.50, it seems to
> work--for me, anyway.
>
> Is this a bug in Emacs 27, or am I misunderstanding something?  I
> thought the point of having newer versions of these core libs on ELPA
> was that they could be used in older--or current--Emacs versions, but
> this doesn't seem to be working reliably.
>

You should file a bug report. It is unclear if a built-in package should
be updated because there are potentially competing indications (or
contradictory).

Look at bug#40971: Updating built-in packages that seq depends on is
broken due to a bug in package.el
-- 
Best regards,
Kevin Vigouroux