The idea was to introduce a ```-nogc``` switch first without introducing ```@gc/@nogc``` attributes as I think it's still controversial whether we should add these. We could even remove the ```-nogc``` switch and keep only ```-vgc```.

The problem is that without attributes these switches can't know which functions should be checked for allocations, so they check all functions. But unittests are usually not interesting in this regard and that's why this check is here.