Issue introduced by a68e4f3b96 ("Use the
new QMetaType API in QVariant") in 6.0, which removed the d.is_null
reset at the same time as it replaced the std::destroy_at /
std::construct_at pair with an assignment operation.
[ChangeLog][QtCore][QVariant] Fixed a bug that would allow the class to
keep returning isNull() = true even after calling setValue().
Fixes: QTBUG-125472
Pick-to: 6.5 6.7
Change-Id: If05cb740b64f42eba21efffd17d13f6b1e8113c2
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Christian Ehrlicher <ch.ehrlicher@gmx.de>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>