GRASS 7: v.to.rast -d produces empty raster when used on areas
Converting areas from vector to raster (v.to.rast) with the -d flag (dense lines) results in an empty raster map.
This is probably/likely because boundaries are not lines in a topolgical sense.
It may be technically chalenging to desify also boundaries. Here one might probably have to distinguish shared boundaries (which can not be densified) and boundaries "owned" by a single area (which could be desified).
In any case, it would be helpful to catch this behavior at least using a warning/error message and by adding information to the manual.