Bash don't interpret ~ path with multiple options.

[Jungsub Shin]

When i try mount aufs, i find some problem with bash.

# mount -o remount,append=~/test_aufs/ro1=ro+wh ~/test_aufs/mount

mount failed with ~/test_aufs/ro1 path isn't exist message.
So i try to debug with strace and i find out bash don't replace ~
path to absolute path.

So i try again with split options lile below.

# mount -o remount -o append=~/test_aufs/ro1=ro+wh ~/test_aufs/mount

It works well. is this bug?? 
Thanks.