~Exists doesn’t preserve filter #18
Description
>>> ex = Exists("x", filter=Q(y=42))
>>> ex.filter
<Q: (AND: ('y', 42))>
>>> (~ex).filter
<Q: (AND: )>
{{ message }}
>>> ex = Exists("x", filter=Q(y=42))
>>> ex.filter
<Q: (AND: ('y', 42))>
>>> (~ex).filter
<Q: (AND: )>