<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/73867>73867</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang-tidy] `readability-identifier-naming` suggest invalid fix when using empty macro arguments
        </td>
    </tr>

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

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

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

<pre>
    When running the fixer for `readability-identifier-naming` on macros that accepts empty arguments the fixer suggests invalid code.

An example is when using `readability-identifier-naming.MacroDefinitionCase=UPPER_CASE` on the following code:
``` c
#define concat(str1, str2) (str1 "" str2)
concat(,"b")
```
which clang-tidy changes to:
``` c
#define CONCAT(str1, str2) (str1 "" str2)
CONCAT("b")
```
.i.e. the required `,` in the expected `CONCAT(,"b")` is removed.

The example running on trunk. Add `--fix` to `Arguments` in the clang-tidy panel to see result of the fixer:
https://godbolt.org/z/vW4jPrT64

This example is a bit fabricated, but we have similar issues with googletests which are macro-heavy.

References
- Empty macro arguments are valid according to: https://gcc.gnu.org/onlinedocs/cpp/Macro-Arguments.html or [link](https://stackoverflow.com/a/7674214).


</pre>
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