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      <base href="https://bugs.llvm.org/">
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Unexpanded parameter pack in 'requires clause' crashes the compiler"
   href="https://bugs.llvm.org/show_bug.cgi?id=45699">45699</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Unexpanded parameter pack in 'requires clause' crashes the compiler
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>10.0
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Macintosh
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>MacOS X
          </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>C++2a
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>s92035@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>blitzrakete@gmail.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=23407" name="attach_23407" title="Diagnostic Log and call trace">attachment 23407</a> <a href="attachment.cgi?id=23407&action=edit" title="Diagnostic Log and call trace">[details]</a></span>
Diagnostic Log and call trace

Steps to Reproduce
==================

- source file: Below as a minimal reproducible sample cpp file.
- This is surely a wrong usage of C++20 requires clause, but it crashes clang
10.0.0 on my Mac running MacOSX 10.15.
- The clang 10.0.0 was compiled and installed from Brew.
- clang++ concept_crash.cpp -std=c++20

template<typename>
concept true_con = true;

template<typename... Args>
void foo(Args&&...) requires true_con<Args> { }

int main() { foo(); }



Result
======

The clang compiler crashes with call trace printed. (Crash log in attachment)</pre>
        </div>
      </p>


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