>
> What seems to be the issue is when a deleted entry of the same name 
> already exists.  I emptied my trash and tried the above recipe: the 
> problem would not occur.  But upon immediate retry the problem appeared, 
> presumably because "test" already existed in the trash.
>

Indeed, this path of the code was recently changed (commit a5197e2240), 
and indeed, when a directory with the same name is trashed twice, it 
fails.  Patch attached.

(It can't be applied yet, I'm still waiting for the end of my paperwork.)