private fun new_property_visibility(modelbuilder: ModelBuilder, mclassdef: MClassDef, nvisibility: nullable AVisibility): MVisibility
	do
		var mvisibility = public_visibility
		if nvisibility != null then
			mvisibility = nvisibility.mvisibility
			if mvisibility == intrude_visibility then
				modelbuilder.error(nvisibility, "Error: `intrude` is not a legal visibility for properties.")
				mvisibility = public_visibility
			end
		end
		if mclassdef.mclass.visibility == private_visibility then
			if mvisibility == protected_visibility then
				assert nvisibility != null
				modelbuilder.error(nvisibility, "Error: `private` is the only legal visibility for properties in a private class.")
			else if mvisibility == private_visibility then
				assert nvisibility != null
				modelbuilder.advice(nvisibility, "useless-visibility", "Warning: `private` is superfluous since the only legal visibility for properties in a private class is private.")
			end
			mvisibility = private_visibility
		end
		return mvisibility
	end