We might end up in this situation if we don't know enough about the
base of the attached lookup. This would generate invalid C++ code.
Pick-to: 6.2 6.3
Change-Id: I210077388d0d1d0d4e9454bd3ba3792af9b42049
Reviewed-by: Maximilian Goldstein <max.goldstein@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>