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    <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 - Clang rejects narrowing conversions in case labels"
   href="https://bugs.llvm.org/show_bug.cgi?id=35287">35287</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Clang rejects narrowing conversions in case labels
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>trunk
          </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>Keywords</th>
          <td>compile-fail
          </td>
        </tr>

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

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

        <tr>
          <th>Component</th>
          <td>-New Bugs
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>miyuki-llvm@miyuki.ru
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Consider the following test case:

$ cat test.cc 
int main()  {
    switch (0u) { 
    case -1: break; 
    }
}

Clang rejects this code when compiling in C++11 and later modes with the
following error:
$ clang++ -std=c++11 -fsyntax-only test.cc 
test.cc:3:10: error: case value evaluates to -1, which cannot be narrowed to
type 'unsigned int' [-Wc++11-narrowing]
    case -1: break; 
         ^

GCC and EDG (ICC 18) accept this code: <a href="https://godbolt.org/g/hVWQgW">https://godbolt.org/g/hVWQgW</a>
ISTM that Clang is wrong (nothing in [stmt.switch] suggests that narrowing
conversions are not allowed in case labels).</pre>
        </div>
      </p>


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