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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 - Explicit template instantiation of nested types"
   href="https://bugs.llvm.org/show_bug.cgi?id=49133">49133</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Explicit template instantiation of nested types
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>11.0
          </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>C++11
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>tomaqa@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>Clang does not accept explicit class template instantiation of a nested type.

Minimal example:

template <typename>
struct Tp {
    using Alias = Tp;
};

/// All should be valid and equivalent
extern template struct Tp<int>;             //< works
extern template struct Tp<int>::Tp;         //< fails
extern template struct Tp<int>::Alias::Tp;  //< fails

error: explicit instantiation of non-templated type 'Tp<int>'

The inst. of nested types should be standard-compliant as well as the first
one.
Also, the error message is quite confusing.
Works in GCC.

<a href="https://stackoverflow.com/questions/34506356/using-typedef-in-template-instantiation-and-extern-template-declaration/34506955#34506955">https://stackoverflow.com/questions/34506356/using-typedef-in-template-instantiation-and-extern-template-declaration/34506955#34506955</a>
<a href="https://stackoverflow.com/questions/11414817/code-duplication-between-typedefs-and-explicit-instantiations">https://stackoverflow.com/questions/11414817/code-duplication-between-typedefs-and-explicit-instantiations</a></pre>
        </div>
      </p>


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