Use of pipe in $(< filename | program) returns null

[root]

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=i386 -mtune=generic 
-fasynchronous-unwind-tables
uname output: Linux saturn.syslang.net 2.6.27.30-170.2.82.fc10.i686.PAE #1 SMP 
Mon Aug 17 08:24:23 EDT 2009 i686 athlon i386 GNU/Linux
Machine Type: i386-redhat-linux-gnu

Bash Version: 3.2
Patch Level: 39
Release Status: release

Description:
        use of $(< filename | program) does not work. It either should or it 
should be properly documented.
        The problem also happens on bash4.

Repeat-By:

        qq=$(< /etc/passwd | grep sys)
        echo $qq
        # result is null

Fix:
        Either fix the docs to tell people that a pipe is not allowed or fix 
the code to allow it.