<html>
    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - parameter passed to std::packaged_task byref stays wrapped with std::reference_wrapper"
   href="https://bugs.llvm.org/show_bug.cgi?id=41032">41032</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>parameter passed to std::packaged_task byref stays wrapped with std::reference_wrapper
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libc++
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>All Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>kirshamir@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>auto task = std::packaged_task<int(const std::vector<int>&)>{
[] (const auto& vec) {
    // clang pass into the method std::reference_wrapper
    // correct behavior should be to unwrap it 
    return std::accumulate(vec.get().begin(), vec.get().end(), 0);
}};

// Code above works only because of the call to 'get' to retrieve the content
of the std::reference_wrapper

// Call the task with some std::vector<int> named vec:
std::thread t = std::thread(std::move(task), std::cref(vec));

Full code:
<a href="http://coliru.stacked-crooked.com/a/cc3b2c44ef5d9834">http://coliru.stacked-crooked.com/a/cc3b2c44ef5d9834</a></pre>
        </div>
      </p>


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