bug#13511: 24.3.50; C-x C-f M-n does not produce buffer filename

[Juri Linkov <juri@jurta.org>]

> The current filename for the buffer is not inserted into the minibuffer.
> You have to press M-n a second time to get ~/tst.txt.
>
> Sometimes, given more content in the file, the minibuffer shows
> ~/images/about.bmp.  I haven't been able to narrow this down to a
> minimal test case.
>
> I was under the impression that C-x C-f M-n should always give the
> filename of the current buffer.

Since ffap doesn't do what you expect, perhaps `C-x C-f M-n' should
give the filename of the current buffer, and second M-n to guess
the filename under cursor using ffap, i.e. to exchange these suggestions
from their current default values.

Or ffap could be improved to better guess the filename under cursor.
Currently it checks whether the file under cursor exists, and
if it doesn't exist it gives the current directory (because of `.'
at the beginning of nonexistent ./images/about.bmp).  Maybe it should not
check the existence of the file and give just ./images/about.bmp
for `C-x C-f M-n'?