#fixed code
                              private void removeUnreferencedVars() {
    CodingConvention convention = codingConvention;

    for (Iterator<Var> it = maybeUnreferenced.iterator(); it.hasNext(); ) {
      Var var = it.next();

      // Remove calls to inheritance-defining functions where the unreferenced
      // class is the subclass.
      for (Node exprCallNode : inheritsCalls.get(var)) {
        NodeUtil.removeChild(exprCallNode.getParent(), exprCallNode);
        compiler.reportCodeChange();
      }

      // Regardless of what happens to the original declaration,
      // we need to remove all assigns, because they may contain references
      // to other unreferenced variables.
      removeAllAssigns(var);

      compiler.addToDebugLog("Unreferenced var: " + var.name);
      Node nameNode = var.nameNode;
      Node toRemove = nameNode.getParent();
      Node parent = toRemove.getParent();

      Preconditions.checkState(
          toRemove.getType() == Token.VAR ||
          toRemove.getType() == Token.FUNCTION ||
          toRemove.getType() == Token.LP &&
          parent.getType() == Token.FUNCTION,
          "We should only declare vars and functions and function args");

      if (toRemove.getType() == Token.LP &&
          parent.getType() == Token.FUNCTION) {
        // Don't remove function arguments here. That's a special case
        // that's taken care of in removeUnreferencedFunctionArgs.
      } else if (NodeUtil.isFunctionExpression(toRemove)) {
        if (!preserveFunctionExpressionNames) {
          toRemove.getFirstChild().setString("");
          compiler.reportCodeChange();
        }
        // Don't remove bleeding functions.
      } else if (parent != null &&
          parent.getType() == Token.FOR &&
          parent.getChildCount() < 4) {
        // foreach iterations have 3 children. Leave them alone.
      } else if (toRemove.getType() == Token.VAR &&
          nameNode.hasChildren() &&
          NodeUtil.mayHaveSideEffects(nameNode.getFirstChild())) {
        // If this is a single var declaration, we can at least remove the
        // declaration itself and just leave the value, e.g.,
        // var a = foo(); => foo();
        if (toRemove.getChildCount() == 1) {
          parent.replaceChild(toRemove,
              new Node(Token.EXPR_RESULT, nameNode.removeFirstChild()));
          compiler.reportCodeChange();
        }
      } else if (toRemove.getType() == Token.VAR &&
          toRemove.getChildCount() > 1) {
        // For var declarations with multiple names (i.e. var a, b, c),
        // only remove the unreferenced name
        toRemove.removeChild(nameNode);
        compiler.reportCodeChange();
      } else if (parent != null) {
        NodeUtil.removeChild(parent, toRemove);
        compiler.reportCodeChange();
      }
    }
  }
#vulnerable code 
                              private void removeUnreferencedVars() {
    CodingConvention convention = compiler.getCodingConvention();

    for (Iterator<Var> it = maybeUnreferenced.iterator(); it.hasNext(); ) {
      Var var = it.next();

      // Regardless of what happens to the original declaration,
      // we need to remove all assigns, because they may contain references
      // to other unreferenced variables.
      removeAllAssigns(var);

      compiler.addToDebugLog("Unreferenced var: " + var.name);
      Node nameNode = var.nameNode;
      Node toRemove = nameNode.getParent();
      Node parent = toRemove.getParent();

      Preconditions.checkState(
          toRemove.getType() == Token.VAR ||
          toRemove.getType() == Token.FUNCTION ||
          toRemove.getType() == Token.LP &&
          parent.getType() == Token.FUNCTION,
          "We should only declare vars and functions and function args");

      if (toRemove.getType() == Token.LP &&
          parent.getType() == Token.FUNCTION) {
        // Don't remove function arguments here. That's a special case
        // that's taken care of in removeUnreferencedFunctionArgs.
      } else if (NodeUtil.isFunctionExpression(toRemove)) {
        if (!preserveFunctionExpressionNames) {
          toRemove.getFirstChild().setString("");
          compiler.reportCodeChange();
        }
        // Don't remove bleeding functions.
      } else if (parent != null &&
          parent.getType() == Token.FOR &&
          parent.getChildCount() < 4) {
        // foreach iterations have 3 children. Leave them alone.
      } else if (toRemove.getType() == Token.VAR &&
          nameNode.hasChildren() &&
          NodeUtil.mayHaveSideEffects(nameNode.getFirstChild())) {
        // If this is a single var declaration, we can at least remove the
        // declaration itself and just leave the value, e.g.,
        // var a = foo(); => foo();
        if (toRemove.getChildCount() == 1) {
          parent.replaceChild(toRemove,
              new Node(Token.EXPR_RESULT, nameNode.removeFirstChild()));
          compiler.reportCodeChange();
        }
      } else if (toRemove.getType() == Token.VAR &&
          toRemove.getChildCount() > 1) {
        // For var declarations with multiple names (i.e. var a, b, c),
        // only remove the unreferenced name
        toRemove.removeChild(nameNode);
        compiler.reportCodeChange();
      } else if (parent != null) {
        NodeUtil.removeChild(parent, toRemove);
        compiler.reportCodeChange();
      }
    }
  } 
                            #location 45 
                            #vulnerability type NULL_DEREFERENCE