History expansion is strangely re-enabled.

[Pierre Gaston]

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: openbsd4.6
Compiler: cc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='openbsd4.6' -DCONF_MACHTYPE='i386-unknown-openbsd4.6' 
-DCONF_VENDOR='unknown' -DLOCALEDIR='/usr/local/share/locale' 
-DPACKAGE='bash' -DSHELL  -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib 
-I/usr/local/include -O2 -pipe
uname output: OpenBSD obsd1 4.6 GENERIC#58 i386
Machine Type: i386-unknown-openbsd4.6

Bash Version: 4.0
Patch Level: 24
Release Status: release

Description:

It looks like a bug, so I'm reporting it
I'm not very familiar with history expansion, so It's perhaps something
I don't understand, in which case I apologize.

Repeat-By:

bash-4.0$ echo foo
foo
bash-4.0$ !echo
echo foo
foo
bash-4.0$ set +H;!((3))
bash: !: event not found
bash-4.0$ !echo
echo foo
foo
bash-4.0$ set +H
bash-4.0$ !echo
bash: !echo: command not found

Fix:
        None