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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 - Incorrect partial specialization selected for zero-length-array type"
   href="https://bugs.llvm.org/show_bug.cgi?id=49808">49808</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Incorrect partial specialization selected for zero-length-array type
          </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>Severity</th>
          <td>enhancement
          </td>
        </tr>

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

        <tr>
          <th>Component</th>
          <td>C++
          </td>
        </tr>

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

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

        <tr>
          <th>CC</th>
          <td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Affected versions:
 - trunk
 - 11.0.1
 - 11.0.0
 - 10.0.1
 - 10.0.0
 - 9.0.1
 - 9.0.0
 - 8.0.1
 - 8.0.0
 - 7.1.0
 - 7.0.1
 - 7.0.0
 - 6.0.1
 - 6.0.0
 - 5.0.1
 - 5.0.0
 - 4.0.1
 - 4.0.0

Driver cmdline:
Note: For clang 4.0.1 and 4.0.0, '-std=c++1z' was substituted for '-std=c++17'
 clang++ -std=c++17

Code:
 #include<type_traits>

 tempalte<typename>
 struct A : std::false_type {};

 template<typename T, auto N>
 struct A<T[N]> : std::true_type {};

 static_assert(A<int[0]>::value);

Expected behaviour:
The static assertion passes; the 'A<T[N]>' partial specialization should've
been selected.

Actual behaviour:
The static assertion fails; the base template is selected

Notes:
Even when adding the following partial specialization, the base template is
still, incorrectly, selected:
 template<typename T>
 struct A<T[0]> : std::true_type {};</pre>
        </div>
      </p>


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