private static void getPostRefs(PyTargetExpression var,
                                  Instruction[] instructions,
                                  int instr,
                                  boolean[] visited,
                                  Collection<PyElement> result) {
    // TODO: Use ControlFlowUtil.process() for forwards CFG traversal
    if (visited[instr]) return;
    visited[instr] = true;
    if (instructions[instr] instanceof ReadWriteInstruction instruction) {
      final PsiElement element = instruction.getElement();
      String name = elementName(element);
      if (Comparing.strEqual(name, var.getName())) {
        final ReadWriteInstruction.ACCESS access = instruction.getAccess();
        if (access.isWriteAccess()) {
          return;
        }
        result.add((PyElement)instruction.getElement());
      }
    }
    for (Instruction instruction : instructions[instr].allSucc()) {
      getPostRefs(var, instructions, instruction.num(), visited, result);
    }
  }
private static void getPostRefs(PyTargetExpression var,
                                  Instruction[] instructions,
                                  int instr,
                                  boolean[] visited,
                                  Collection<PyElement> result)