private boolean isSameLen(DataType dt, Data existingData) {
		return existingData.getLength() == dt.getLength() ||
			(dt instanceof Dynamic dyDT && dyDT.canSpecifyLength());
	}
Logic to test if a Data instance is replaceable with a data type.
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf/DWARFDataInstanceHelper.java