[mew-int 2458] Insufficient error reporting in case of missing file

[Harald Hanche-Olsen]

I sent out two mails today, both with the same jpeg file attached.
Unfortunately, between the first and second email I was distracted and
accidentally deleted the jpeg file. So, for the second email, I hit
C-c C-a, then C-c C-l - and rather than navigate to the file (which
would have alerted me to its nonexistence) I just hit M-p a few times
until the right filename appeared in the minibuffer, and hit return.
This resulted in no error message. Then I hit C-c C-c to send the
message, answered y to the question, and were treated to these
messages in quick succession in the minibuffer:

Wrote /Users/hanche/Mew/draft/2
Making a message...
nil

and nothing more happened; just that nil in the minibuffer.
I must admit I had no idea what was going on until I noticed the
missing jpeg.

So here is my humble wish: Better error reporting in this case.

(Mew version 5.2.51.)

- Harald