array subscripts act differently for integers(ie. let)

[emanuelczirai]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-unknown-linux-gnu' 
-DCONF_VENDOR='unknown' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' 
-DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib  
-D_FORTIFY_SOURCE=2 -march=x86-64 -mtune=generic -O2 -pipe 
-fstack-protector-strong --param=ssp-buffer-size=4 
-DDEFAULT_PATH_VALUE='/usr/local/sbin:/usr/local/bin:/usr/bin' 
-DSTANDARD_UTILS_PATH='/usr/bin' -DSYS_BASHRC='/etc/bash.bashrc' 
-DSYS_BASH_LOGOUT='/etc/bash.bash_logout'
uname output: Linux manji 3.19.0-gbfa76d49 #28 SMP Mon Feb 9 14:29:14 
CET 2015 x86_64 GNU/Linux
Machine Type: x86_64-unknown-linux-gnu

Bash Version: 4.3
Patch Level: 33
Release Status: release

Description:
	when dealing with integer operations(let, ++), "bad array subscript" 
errors can happen because subscripts get unquoted (and evaluated even 
though they are in single quotes); unlike what happens when dealing with 
strings.

Repeat-By:
	please see attached bash script to reproduce because that explains it 
much better than I could in words.

Thank you.

subscripty_integer.bash
Description: Text Data