Here strings and brace expansion not working as per man page

[Conor McCarthy]

Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i686' -DCONF_OSTYPE='linu
x-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu' -DCONF_VENDOR='pc' -DLOCALEDIR='/usr/
local/share/locale' -DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./incl
ude -I./lib   -g -Wno-parentheses -Wno-format-security -fno-inline
uname output: Linux gomez 2.6.33.4-smp #2 SMP Wed May 12 22:47:36 CDT 2010 i686
Intel(R) Core(TM)2 Duo CPU     E8400  @ 3.00GHz GenuineIntel GNU/Linux
Machine Type: i686-pc-linux-gnu

Bash Version: 4.4
Patch Level: 12
Release Status: release

Description:
        Here strings are documented as:

           [n]<<<word

        The word undergoes brace  expansion,  tilde  expansion,  parameter  and
        variable  expansion,  command  substitution,  arithmetic expansion, and
        quote removal.

        But brace expansion is not applied:

        $ read zz <<< {1..9}
        $ echo $zz
        {1..9}

        The codepath from write_here_string() does not pass through any
        expand_xxx functions which apply brace expansion, AFAICT.

        (bash was built with -fno-inline for gdb only)

Repeat-By:
        $ read zz <<< {1..9}
        $ echo $zz
        {1..9}

        Expected behaviour would be similar to:
        $ read zz <<< $(echo {1..9})
        $ echo $zz
        1 2 3 4 5 6 7 8 9
Fix:
        I have hacked a call to brace_expand() into write_here_string()
        before it calls expand_string_unsplit_to_string() as a possible
        solution, though I suspect there's a cleaner way... perhaps an
        alternate expand_ function is available?
        (I can clean this up and submit it if I'm barking up the right tree.)