Subject: .elc file - possibly outdated backward compatibility comments

From: Stefan Kangas <[email-masked]>
Date: Wed, 22 Jan 2020 09:44:14 +0100

In the .elc files on my machine, I see the following:

    ;;; This file uses dynamic docstrings, first added in Emacs 19.29.
    
    ;;; This file does not contain utf-8 non-ASCII characters,
    ;;; and so can be loaded in Emacs versions earlier than 23.

I have the following suggestions/questions:

1. Is it still correct that the byte compiled file can be loaded on
   Emacs 22?  We have (at least) one new opcode not supported by
   Emacs 22 (see e.g. commit 88549ec38).

   And AFAIK, Emacs crashes on incorrect opcodes.

   If the comment is incorrect, we should consider removing or
   changing it.

2. Change the first line to no longer mention Emacs 19.29.  Emacs
   versions before 19.29 are no longer relevant, so there is need to
   say this.

3. Following up on point 2, I also see:
   
       "\n;;; This file uses "
       (if dynamic-docstrings
           "dynamic docstrings, first added in Emacs 19.29"
         "opcodes that do not exist in Emacs 18")
   
   I'm not sure what to do here, but it doesn't seem to make sense to
   mention Emacs 18 in any case.  Of course, this file might use
   opcodes that do not exist in Emacs 23, or perhaps an even later
   version.

Or, these points are all moot because no one cares what these files
says, and it should anyways be kept for hysterical reasons.  I just
don't know.  :-)  So WDYT?

Best regards,
Stefan Kangas