<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/147217>147217</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Invalid attribute accepted dealing with # and ## operators
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          pinskia
      </td>
    </tr>
</table>

<pre>
    Forwarded from https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120978 because clang is the only major compiler which accepts this (EDG, GCC and MSVC all reject this for having # and ## operators outside of macros).

```
[[ignored::ignored(##)]]int main(){}
```

The way I read the standard is during phase 4, this should be diagnostic as invalid. Which is exactly how GCC, EDG and MSVC all do as `##` operator is invalid outside of the function like macros.

But I could be reading the spec wrong but with clang being the odd one out though; it looks more likely a clang issue.
</pre>
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