Invalid array subscript (single backslash) causes assertion failure

[Ian Robertson]

Configuration Information [Automatically generated, do not change]:
Machine: i486
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i486' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i486-pc-linux-gnu' 
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' 
-DSHELL -DHAVE_CONFIG_H   -I.  -I../bash -I../bash/include -I../bash/lib 
  -g -O2 -Wall
uname output: Linux redacted 2.6.22-14-generic #1 SMP Tue Feb 12 
07:42:25 UTC 2008 i686 GNU/Linux
Machine Type: i486-pc-linux-gnu

Bash Version: 3.2
Patch Level: 25
Release Status: release

Description:
        Bash prints the following lines and dumps core:

        malloc: ../bash/arrayfunc.c:616: assertion botched
        free: start and end chunk sizes differ
        last command: ${foo[\]}
        Aborting...Aborted (core dumped)

Repeat-By:
        Enter the following line in interactive mode:

        ${foo[\]}

Fix:
        Obviously not a valid construct, but nevertheless shouldn't crash.