bash 4 parse error on here-document in $()

[Martin Sebor]

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i386-redhat-linux-gnu' 
-DCONF_VENDOR='redhat' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' 
-DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib  -D_GNU_SOURCE 
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2 -g -pipe -Wall 
-Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector 
--param=ssp-buffer-size=4 -m32 -march=i586 -mtune=generic 
-fasynchronous-unwind-tables
uname output: Linux mslaptop 2.6.30.5-43.fc11.i586 #1 SMP Thu Aug 27 
21:18:54 EDT 2009 i686 i686 i386 GNU/Linux
Machine Type: i386-redhat-linux-gnu

Bash Version: 4.0
Patch Level: 23
Release Status: release

Description:
        Bash 4.0 errors on a here-document enclosed in $(). For example:
        x=$(cat <<EOF
        foo
        bar
        EOF)
        Ctrl+D
        -bash: unexpected EOF while looking for matching `)'
        -bash: syntax error: unexpected end of file

Repeat-By:
        Save the following script in a file named t.sh, execute the file
        and observe the parse error:
        ./t.sh: line 7: unexpected EOF while looking for matching `)'
        ./t.sh: line 13: syntax error: unexpected end of file

        #!/bin/bash
        x=`cat <<EOF
        foo
        bar
        EOF`

        y=$(cat <<EOF
        foo
        bar
        EOF)

        [ "$x" != "$y" ] && exit 1