bug#39612: 26.3; rmail-summary-delete-forward: Wrong type argument: number-or-marker-p, nil

[Ed Sabol]

I kept getting the error "Wrong type argument: number-or-marker-p, nil" if I
tried to delete a message immediate after retrieving new messages. I finally
figured out a solution. In `rmail-summary-delete-forward', please change:

      (with-current-buffer rmail-buffer
        (rmail-delete-message)
        (setq del-msg rmail-current-message))

to

      (with-current-buffer rmail-buffer
        (setq del-msg rmail-current-message)
        (rmail-delete-message))

For some inexplicable reason, rmail-current-message becomes nil after
executing `rmail-delete-message' *sometimes*. I'm not sure under what
circumstances it does though, so I can't give you a precise recipe to
reproduce it. Changing the order of these two forms completely fixes this
problem for me though. I would really appreciate it if someone committed this
minor change.

Is the `(rmail-summary-mark-deleted del-msg)' on the following line even
needed? rmail-delete-message calls rmail-summary-mark-deleted. Seems like
duplicate effort. If you get rid of that line, then you don't need the
del-msg variable at all, which would simplify this code considerably and also
eliminate the problem.


In GNU Emacs 26.3 (build 1, x86_64-pc-linux-gnu, X toolkit)
 of 2019-11-19 built on heabox
Windowing system distributor 'The X.Org Foundation', version 11.0.12004000
System Description:     Scientific Linux release 7.7 (Nitrogen)

Recent messages:
Expunging deleted messages...done
Computing summary lines...done
Saving file /Home/lhea2/sabol/Mail/cron...
Wrote /Home/lhea2/sabol/Mail/cron [2 times]
Computing summary lines...done
Auto-saving...done
Mark set [2 times]
Region copied to kill buffer.
Making completion list... [2 times]
Region copied to kill buffer.

Configured using:
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