<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/143708>143708</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Confusing Error Message with placement new
        </td>
    </tr>

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

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

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

<pre>
    This code: https://godbolt.org/z/535xcWEff

Gives the following error with trunk Clang:

```
<source>:8:9: error: no matching 'operator new' function for non-allocating placement new expression; include <new>
    8 |         new (&s) std::span(s_);
```

However, I have the suggested `#include <new>`. The problem is not the placement new itself, but that the code tries to mutate a `const` member variable. If the `const` is removed on line 5 the code compiles correctly. An error message pointing towards the `const` member variable would be appreciated.

(I hit this problem with a type alias in a library that includes the extra `const`)
</pre>
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