<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/63537>63537</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            #include_next <same_header_name> gives error in Clang-based tools, but not Clang
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            libclang
      </td>
    </tr>

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

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

<pre>
    Consider this header `stdio.h`:
```cpp
// exists so it can be put in a modulemap...
#include_next <stdio.h>

// and also so we can mark a few things nodiscard
[[nodiscard]] FILE* tmpfile();
[[nodiscard]] FILE* fopen(const char* filename, const char* mode);
// ...
```
this gives the following error in Clang-based tooling (e.g. clangd and a Clang-aware Doxygen), but not Clang:
```
Main file cannot be included recursively when building a preamble clang(pp_including_mainfile_in_preamble)
Unknown type name 'FILE'
```

I don't necessarily know if this is a bug, or if the driver is passing info to Clang so it doesn't error out. Sadly, I can't seem to work it out.
</pre>
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