public void descendReplace(VarnodeAST vn) {
		ListIterator<PcodeOp> iter = vn.descend.listIterator();
		while (iter.hasNext()) {
			PcodeOp op = iter.next();
			if (op.getOutput() == this) {
				continue;		// Cannot be input to your own definition
			}
			int num = op.getNumInputs();
			for (int i = 0; i < num; ++i) {
				// Find reference to vn
				if (op.getInput(i) == vn) {
					vn.removeDescendant(op);
					op.setInput(null, i);
					addDescendant(op);
					op.setInput(this, i);
					break;
				}
			}
		}
	}
Replace all of parameter vn's references with this
@param vn  Varnode whose references will get replaced
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/VarnodeAST.java