Negative array subscript with unset

[Chris F.A. Johnson]

  I all versions I have tried, unsetting an array element using a
  negative index fails:

$ array=( q w e r t y )
$ unset 'array[-1]'
bash: [-1]: bad array subscript


--
   Chris F.A. Johnson, <http://cfajohnson.com/>
   Author:
   Pro Bash Programming: Scripting the GNU/Linux Shell (2009, Apress)
   Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)