If we try to lookup the length of a generic QVariant, we fail, and so
far crashed. We should ideally detect that we are dealing with an array
(and thus length is a known, available property), but for now simply
reject compilation to C++.
Pick-to: 6.4
Fixes: QTBUG-109164
Change-Id: I9d4149ac09a351754d012dbc829774413d6b32eb
Reviewed-by: Semih Yavuz <semih.yavuz@qt.io>
Reviewed-by: Sami Shalayel <sami.shalayel@qt.io>