apparent bug involving completion and eval

[a050106 . 1 . keeLae3x]

Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i686' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu' 
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/local/bash-3.0/share/locale' 
-DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H  -I.  -I. -I./include -I./lib   -g -O2
uname output: Linux gilead 2.4.18-686 #1 Sun Apr 14 11:32:47 EST 2002 i686 
unknown
Machine Type: i686-pc-linux-gnu

Bash Version: 3.0
Patch Level: 0
Release Status: release

Description:

        In certain circumstances, attempting completion seems to cause 
        Bash to temporarily forget an alias.  This seems
        to occur when `eval' is used in the completion function.

Repeat-By:
        
        To reproduce the problem, I first give the following 3 commands:

                alias c5=echo
                cf5() { eval true; }
                complete -F cf5 c5

        I then type "c5 a" at the command line.  The cursor is now
        just after the `a'.  I then request completion by hitting
        Tab (no completions are found, of course).  I then hit Enter.
        Bash then gives the message "-bash: c5: command not found".

        If I redefine the function cf5 as follows:

                cf5() { true; }

        and then try the same thing, the problem doesn't occur.  That is,
        Bash finds the `c5' command and runs it.

        By the way, the error message quoted above begins with "-bash",
        not "bash" as in older versions of Bash.  While I'm aware that
        making argument 0 begin with a dash is the way to make Bash act
        as a login shell, I don't see any reason for the dash to appear
        in error messages.  (Maybe I should log this as a separate bug,
        but arguably it's not a bug, and it seems too trivial for a
        separate bug report anyway.)