<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/145240>145240</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Clang] UCN in preprocessor-pasted identifier not resolved to unicode
        </td>
    </tr>

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

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

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

<pre>
    With the snippet:
```
#define CAT(a,b) a##b

char foo\u00b5;
char*p = &CAT(foo, \u00b5);
```
Clang resolves the variable name as `"fooµ"`, and the concatenated reference to it next line as `"foo\u00b5"`, then error on undeclared reference. Other implementations instead treat both the same: https://godbolt.org/z/M1fejPK36

Wasn't encountered in real world, just a what-if test I came up for my implementation.
</pre>
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