private boolean hasSizeChange() {
		int newTypeLength = newType.getLength();
		if (newTypeLength == composite.getLength()) {
			return false;
		}
		if (newType.getLength() < composite.getLength()) {
			DataTypeComponent[] components = composite.getDefinedComponents();
			for (DataTypeComponent dtc : components) {
				if (dtc.getOffset() + dtc.getLength() > newTypeLength) {
					return false;
				}
			}
		}
		return true;
	}
@return true if the new field data-type will cause the size of the union to change
Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/RetypeUnionFieldTask.java