Referencing empty array with "set -u" active throws error

[jens . schmidt35]

Configuration Information [Automatically generated, do not change]:
Machine: sparc
OS: solaris2.9
Compiler: /sapmnt/global/tools/compiler/SS11/SUNWspro/bin/cc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='sparc' 
-DCONF_OSTYPE='solaris2.9' -DCONF_MACHTYPE='sparc-sun-solaris2.9' 
-DCONF_VENDOR='sun' 
-DLOCALEDIR='/sapmnt/oraicall/home/tools/bash-4.1/share/locale' 
-DPACKAGE='bash' -DSHELL  -DHAVE_CONFIG_H -DSOLARIS   -I.  -I. -I./include 
-I./lib -I./lib/intl 
-I/net/sapmnt.home2/oraic/tmp/bash_sunos_sun4u/bash-4.1/lib/intl  -g
uname output: SunOS us0111 5.9 Generic_117171-12 sun4u sparc SUNW,Sun-Fire-V440
Machine Type: sparc-sun-solaris2.9

Bash Version: 4.1
Patch Level: 0
Release Status: release

Description:
   Referencing empty array with "set -u" active throws unbound variable error.

Repeat-By:
  $ set -u
  $ declare -a array
  $ array=( )
  $ echo "${arr...@]}"
  bash: arr...@]: unbound variable

  For an empty "$@" this does not throw an "unbound" error, which seems to be 
an inconsistent behaviour to me.

Workaround:
  Use the infamous empty array work-around:
  $ echo ${argv[0]+"${ar...@]}"}