ln can't backup directories

[Bert Wesarg]

Hi all,

I'm failing in creating a symlink where the destination is a directory
and do a backup of this directory. This is what I tried:

$ mkdir a
$ ln -s --no-target-directory --backup=numbered b a
ln: `a': cannot overwrite directory

Looking at the code I can seen the reason, the backup rename() is
never executed, because the check whether the target is a directory
comes first.

Any hints whether this is a bug of ln or how I can create the link
while preserving the destination as an backup are more than welcomed.

Thanks.
Bert