Indirect parameter access combined with Assign Default Values

[Andre Holzhey]

Configuration Information [Automatically generated, do not change]:
Machine: arm
OS: linux-gnueabihf
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='arm'
-DCONF_OSTYPE='linux-gnueabihf'
-DCONF_MACHTYPE='arm-unknown-linux-gnueabihf' -DCONF_VENDOR='unknown'
-DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H
  -I.  -I../bash -I../bash/include -I../bash/lib  -D_FORTIFY_SOURCE=2 -g
-O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat
-Werror=format-security -Wall
uname output: Linux FrolleinPi 3.10.25+ #622 PREEMPT Fri Jan 3 18:41:00
GMT 2014 armv6l GNU/Linux
Machine Type: arm-unknown-linux-gnueabihf

Bash Version: 4.2
Patch Level: 37
Release Status: release

Description:
        ${!Name:=Value} produces variables with illegal names. This does not
directly disturb scripting, but it seems to open a terrible universe...
        Anyway, It would be nice, to make this combination work.
        Reproducible on bash 4.1.5 on 86_x64 (Debian)
Repeat-By:
        Name=N1
        echo "${!Name:=Value}"
        (gives 'Value')
        set | grep Value
        (gives '!Name=Value')
        

Fix:
        [Description of how to fix the problem.  If you don't know a
        fix for the problem, don't include this section.]

dead.bashbug
Description: Text document