#vulnerable code 
                              private static boolean isArgumentOfSafeFunctionCall(Tree tree) {
    Tree parent = tree.getParent();
    if (parent.is(Tree.Kind.FUNCTION_CALL)) {
      FunctionCallTree functionCall = (FunctionCallTree) parent;
      ExpressionTree callee = functionCall.callee();
      if (callee.is(Tree.Kind.NAMESPACE_NAME)) {
        String qualifiedName = ((NamespaceNameTree) callee).qualifiedName();
        return SAFE_FUNCTIONS.stream().anyMatch(qualifiedName::equalsIgnoreCase);
      }
    }
    return false;
  } 
                            #location 3 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              private static boolean isArgumentOfSafeFunctionCall(Tree tree) {
    if (!tree.getParent().is(Tree.Kind.CALL_ARGUMENT) || !tree.getParent().getParent().is(Tree.Kind.FUNCTION_CALL)) {
      return false;
    }

    FunctionCallTree functionCall = (FunctionCallTree) tree.getParent().getParent();
    ExpressionTree callee = functionCall.callee();
    if (callee.is(Tree.Kind.NAMESPACE_NAME)) {
      String qualifiedName = ((NamespaceNameTree) callee).qualifiedName();
      return SAFE_FUNCTIONS.stream().anyMatch(qualifiedName::equalsIgnoreCase);
    }

    return false;
  }