#vulnerable code 
                              private Node inlineReturnValue(Node callNode, Node fnNode) {
    Node block = fnNode.getLastChild();
    Node callParentNode = callNode.getParent();

    // NOTE: As the normalize pass guarantees globals aren't being
    // shadowed and an expression can't introduce new names, there is
    // no need to check for conflicts.

    // Create an argName -> expression map, checking for side effects.
    Map<String, Node> argMap =
        FunctionArgumentInjector.getFunctionCallParameterMap(
            fnNode, callNode, this.safeNameIdSupplier);

    Node newExpression;
    if (!block.hasChildren()) {
      Node srcLocation = block;
      newExpression = NodeUtil.newUndefinedNode(srcLocation);
    } else {
      Node returnNode = block.getFirstChild();
      Preconditions.checkArgument(returnNode.getType() == Token.RETURN);

      // Clone the return node first.
      Node safeReturnNode = returnNode.cloneTree();
      Node inlineResult = FunctionArgumentInjector.inject(
          null, safeReturnNode, null, argMap);
      Preconditions.checkArgument(safeReturnNode == inlineResult);
      newExpression = safeReturnNode.removeFirstChild();
    }

    callParentNode.replaceChild(callNode, newExpression);
    return newExpression;
  } 
                            #location 24 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              private Node inlineReturnValue(Node callNode, Node fnNode) {
    Node block = fnNode.getLastChild();
    Node callParentNode = callNode.getParent();

    // NOTE: As the normalize pass guarantees globals aren't being
    // shadowed and an expression can't introduce new names, there is
    // no need to check for conflicts.

    // Create an argName -> expression map, checking for side effects.
    Map<String, Node> argMap =
        FunctionArgumentInjector.getFunctionCallParameterMap(
            fnNode, callNode, this.safeNameIdSupplier);

    Node newExpression;
    if (!block.hasChildren()) {
      Node srcLocation = block;
      newExpression = NodeUtil.newUndefinedNode(srcLocation);
    } else {
      Node returnNode = block.getFirstChild();
      Preconditions.checkArgument(returnNode.getType() == Token.RETURN);

      // Clone the return node first.
      Node safeReturnNode = returnNode.cloneTree();
      Node inlineResult = FunctionArgumentInjector.inject(
          safeReturnNode, null, argMap);
      Preconditions.checkArgument(safeReturnNode == inlineResult);
      newExpression = safeReturnNode.removeFirstChild();
    }

    callParentNode.replaceChild(callNode, newExpression);
    return newExpression;
  }