<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/79677>79677</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang++ on Windows fails to define std::any when disabling RTTI
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

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

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

<pre>
    Disabling RTTI on Clang on Windows prevents std::any from being defined. This does not happen when RTTI is left enabled, or with RTTI disabled on Clang on Linux.

**Repro**
main.cpp:
```
#include <any>

int main()
{
    std::any a;
}
```
Errors generated with RTTI disabled (Windows only):
```
>clang++ -std=c++17 -fno-rtti main.cpp
main.cpp:5:5: error: use of undeclared identifier 'std'
 std::any a;
    ^
1 error generated.
```
No errors generated with RTTI left enabled:
`>clang++ -std=c++17 main.cpp`

```
clang version 16.0.5
Target: i686-pc-windows-msvc
Thread model: posix
```
</pre>
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