#vulnerable code 
                              private Node aliasAndInlineArguments(
      Node fnTemplateRoot, LinkedHashMap<String, Node> argMap,
      Set<String> namesToAlias) {

    if (namesToAlias == null || namesToAlias.isEmpty()) {
      // There are no names to alias, just inline the arguments directly.
      Node result = FunctionArgumentInjector.inject(
          compiler, fnTemplateRoot, null, argMap);
      Preconditions.checkState(result == fnTemplateRoot);
      return result;
    } else {
      // Create local alias of names that can not be safely
      // used directly.

      // An arg map that will be updated to contain the
      // safe aliases.
      Map<String, Node> newArgMap = Maps.newHashMap(argMap);

      // Declare the alias in the same order as they
      // are declared.
      List<Node> newVars = Lists.newLinkedList();
      // NOTE: argMap is a linked map so we get the parameters in the
      // order that they were declared.
      for (Entry<String, Node> entry : argMap.entrySet()) {
        String name = entry.getKey();
        if (namesToAlias.contains(name)) {
          if (name.equals(THIS_MARKER)) {
            boolean referencesThis = NodeUtil.referencesThis(fnTemplateRoot);
            // Update "this", this is only necessary if "this" is referenced
            // and the value of "this" is not Token.THIS, or the value of "this"
            // has side effects.

            Node value = entry.getValue();
            if (value.getType() != Token.THIS
                && (referencesThis
                    || NodeUtil.mayHaveSideEffects(value, compiler))) {
              String newName = getUniqueThisName();
              Node newValue = entry.getValue().cloneTree();
              Node newNode = NodeUtil.newVarNode(newName, newValue)
                  .copyInformationFromForTree(newValue);
              newVars.add(0, newNode);
              // Remove the parameter from the list to replace.
              newArgMap.put(THIS_MARKER,
                  Node.newString(Token.NAME, newName)
                      .copyInformationFromForTree(newValue));
            }
          } else {
            Node newValue = entry.getValue().cloneTree();
            Node newNode = NodeUtil.newVarNode(name, newValue)
                .copyInformationFromForTree(newValue);
            newVars.add(0, newNode);
            // Remove the parameter from the list to replace.
            newArgMap.remove(name);
          }
        }
      }

      // Inline the arguments.
      Node result = FunctionArgumentInjector.inject(
          compiler, fnTemplateRoot, null, newArgMap);
      Preconditions.checkState(result == fnTemplateRoot);

      // Now that the names have been replaced, add the new aliases for
      // the old names.
      for (Node n : newVars) {
        fnTemplateRoot.addChildToFront(n);
      }

      return result;
    }
  } 
                            #location 7 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              private Node aliasAndInlineArguments(
      Node fnTemplateRoot, LinkedHashMap<String, Node> argMap,
      Set<String> namesToAlias) {

    if (namesToAlias == null || namesToAlias.isEmpty()) {
      // There are no names to alias, just inline the arguments directly.
      Node result = FunctionArgumentInjector.inject(
          compiler, fnTemplateRoot, null, argMap);
      Preconditions.checkState(result == fnTemplateRoot);
      return result;
    } else {
      // Create local alias of names that can not be safely
      // used directly.

      // An arg map that will be updated to contain the
      // safe aliases.
      Map<String, Node> newArgMap = Maps.newHashMap(argMap);

      // Declare the alias in the same order as they
      // are declared.
      List<Node> newVars = Lists.newLinkedList();
      // NOTE: argMap is a linked map so we get the parameters in the
      // order that they were declared.
      for (Entry<String, Node> entry : argMap.entrySet()) {
        String name = entry.getKey();
        if (namesToAlias.contains(name)) {
          if (name.equals(THIS_MARKER)) {
            boolean referencesThis = NodeUtil.referencesThis(fnTemplateRoot);
            // Update "this", this is only necessary if "this" is referenced
            // and the value of "this" is not Token.THIS, or the value of "this"
            // has side effects.

            Node value = entry.getValue();
            if (!value.isThis()
                && (referencesThis
                    || NodeUtil.mayHaveSideEffects(value, compiler))) {
              String newName = getUniqueThisName();
              Node newValue = entry.getValue().cloneTree();
              Node newNode = NodeUtil.newVarNode(newName, newValue)
                  .copyInformationFromForTree(newValue);
              newVars.add(0, newNode);
              // Remove the parameter from the list to replace.
              newArgMap.put(THIS_MARKER,
                  Node.newString(Token.NAME, newName)
                      .copyInformationFromForTree(newValue));
            }
          } else {
            Node newValue = entry.getValue().cloneTree();
            Node newNode = NodeUtil.newVarNode(name, newValue)
                .copyInformationFromForTree(newValue);
            newVars.add(0, newNode);
            // Remove the parameter from the list to replace.
            newArgMap.remove(name);
          }
        }
      }

      // Inline the arguments.
      Node result = FunctionArgumentInjector.inject(
          compiler, fnTemplateRoot, null, newArgMap);
      Preconditions.checkState(result == fnTemplateRoot);

      // Now that the names have been replaced, add the new aliases for
      // the old names.
      for (Node n : newVars) {
        fnTemplateRoot.addChildToFront(n);
      }

      return result;
    }
  }