Will try. Actually this issue is not too important for gintro and cairo, because for all the gobject based objects the cast is correct, and for cairo I can provide a uref() function for each cairo type with correct cast.
The question is more if the ref type of GC_unref() should matter for Nim 2.0. Because people writing bindings have to care for this, and when the type matters, then writing bindings may become harder. But I assume that currently no one knows if GC_unref() will be available at all for Nim 2.0. I can remember years ago when ARC had no name and we discussed the Bacon/Dingle paper it was intended to fully remove GC_ref()/GC_unref() which would have been a really serious problem for bindings.
