<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/55306>55306</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Should #elifdef and #elifndef have a portability warning?
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            good first issue,
            clang:frontend,
            clang:diagnostics
      </td>
    </tr>

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

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

<pre>
    These are new features of C2x, but they're supported as a conforming extension in older versions of Clang. However, there's no pedantic warning given about them being a Clang extension in older language modes, so users may be surprised when porting to another compiler. See https://godbolt.org/z/MdK476q7b as an example. Should we be issuing a pedantic warning here?
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJxtkd2OnDAMhZ8GbqwiJgzzc8HF7lajSlWv2hdwiIFUIaZJmNnp09dhuq3UrUQU2Safz7E1m3v3baJIgIHA0w0GwrQGisADvKjXQr2AXhOkie6FOspPcV0WDokMYASEnv3AYbZ-BHpN5KNlD9YDO0MBrhRy4kFz6McKPvGNJJ3BAg0k1AieYSGDPtkebhh8xo32Sh5Q86P9DJpyGh-g_3XL-RVHgpkNxdwhMqxRNMCMd3kv4sMSbBTxt0ng2UhmJgb0nOWIn3mxjkIFX4lgSmmJRfNUqIt8IxvNLlUcRol-yvliPu-Phx9HvQ3DiyicF0fyeOLVSRfKXW2M60P6O5PbBJpLabrGnJszlskmR93v54VqyNnB0CDwP6HP8YRXykBxgNo6m-5vzIxbg-v-0W7TtOpK7Eng3PXt-rAE_k59kjDLzGO7tG1TH8qpw7NpyPTqjMdhUKbVraH97tzsTupUDyLWoSYXu6J9LpQamQ0MNsS0GZbFqrwCufq8GFEyBPayNPO-YiyOnqNMJuZi-7G0naqVqtv6sFP1oWmr5khD3eNpVzfn00m3xb6mGa2rsou8kjJ0myG9jlGKzsYU_xYxRjt6ok2s8HFNE4fuCUXTMzo3oy832d3m_hcpMA0C">