<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/60542>60542</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Header modules should do a bit more work when diagnosing unqualified names in their own namespace
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang:modules,
            clang:diagnostics
      </td>
    </tr>

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

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

<pre>
    ```cpp
namespace std {
  void example()
  {
    return is_lvalue_reference_v<T>;
 }
} // namespace std
```
`clang++ -fmodules above_snippet.cpp` will diagnose as follows:
```

```
error: use of undeclared identifier 'is_lvalue_reference_v'
```

However, if we qualify `is_lvalue_reference_v` with `std::`, this magically changes to
```
error: declaration of 'is_lvalue_reference_v' must be imported from module 'std.type_traits.detail.categories' before it is required
```

This discrepancy is a bit weird: the compiler should know that `is_lvalue_reference_v` implies `std::is_lvalue_reference_v` when in `namespace std`, and thus diagnose it in the same way for both cases.
</pre>
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