<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/70323>70323</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang-tidy] incorrect `misc-const-correctness` warning emitted for C++17 fold expression
        </td>
    </tr>

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

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

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

<pre>
    The following snippet can be used to "concatenate" a series of variadic parameters, thanks to a fold expression.

`clang-tidy` emits `misc-const-correctness` for the line declaring `oss`. I think it should not.

Command to run the example:
> clang-tidy --checks=misc-const-correctness --extra-arg=-std=c++20 test.cpp

```c++
#include <concepts>
#include <sstream>
#include <string>

//! Concatenate arguments in a @c std::string using a @c std::ostringstream.
template <typename... Args> requires (sizeof...(Args) > 0)
std::string concatenate(Args&&... args)
{
    std::ostringstream oss;
    (oss << ... << std::forward<Args>(args));
    return oss.str();
}
```

I'm using `Ubuntu LLVM version 17.0.4` version of `clang-tidy`.
</pre>
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