<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/121258>121258</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang-trunk rejects valid friend declaration of private base class with very confusing diagnostic
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          wangbo15
      </td>
    </tr>
</table>

<pre>
    The following code is rejected by clang-trunk:

```c++
struct payload {};

struct base: private payload {
};

struct derived: base {
    friend class payload;
};
```

The diagnostic is hard to understand. It seems the compiler treats the private inheritance statement as a member declaration or something else here:

```c++
<source>:7:18: error: 'payload' is a private member of 'payload'
    7 |     friend class payload;
      | ^
<source>:3:14: note: constrained by private inheritance here
    3 | struct base: private payload {
      | ^~~~~~~~~~~~~~~
<source>:1:8: note: member is declared here
    1 | struct payload {};
      |        ^
1 error generated.
```

GCC and MSVC both accept it.

Please see [https://godbolt.org/z/4da5TbvYe](https://godbolt.org/z/4da5TbvYe)
</pre>
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