Bad array subscript error when trying to increment an associative array element

Question

I can create an associative array and assign an integer to a key that contains a single quote in it:

Answer 1

Turn off multiple evaluation^* of associative array subscripts with following command and it'll work.

shopt -s assoc_expand_once

^* An example showing the default behavior and assoc_expand_once's effect:

$ v1=42
$ v2='$v1'
$ declare -A foo
$ foo[$v2]=
$ declare -p foo
declare -A foo=(["\$v1"]="" )
$ (( foo[$v2]++ ))
$ declare -p foo
declare -A foo=([42]="1" ["\$v1"]="" )
$
$ shopt -s assoc_expand_once
$ (( foo[$v2]++ ))
$ declare -p foo
declare -A foo=([42]="1" ["\$v1"]="1" )