int getLineNumber(AbstractMsType type) {
		if (type instanceof UserDefinedTypeSourceAndLineMsType udtSLType) {
			return udtSLType.getLineNumber();
		}
		else if (type instanceof UserDefinedTypeModuleSourceAndLineMsType udtMSLType) {
			return udtMSLType.getLineNumber();
		}
		return -1;
	}
Returns the offset of the Base Class within the inheriting class
@param type the PDB type being inspected
@return the offset or -1 if problem retrieving value
Ghidra/Features/PDB/src/main/java/ghidra/app/util/pdb/pdbapplicator/UdtSourceLineTypeApplier.java