Bash arrays and negative subscripts, yes or no?

Question

The GNU bash manual tells me

An indexed array is created automatically if any variable is assigned to using the syntax

name[subscript]=v         


        

Answer 1

The negative subscript works perfectly fine for me on my computer with Ubuntu 14.04 / GNU bash version 4.3.11(1) however it returns:

line 46: [-1]: bad array subscript

When I try to run the same script on 4.2.46(1). I