<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 - "friend Foo< args >;" sometimes gives friendship to other template instances"
   href="https://bugs.llvm.org/show_bug.cgi?id=49472">49472</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>"friend Foo< args >;" sometimes gives friendship to other template instances
          </td>
        </tr>

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

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

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

        <tr>
          <th>OS</th>
          <td>All
          </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>jchl@arista.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>Given the following program [<a href="https://godbolt.org/z/c9Y895">https://godbolt.org/z/c9Y895</a>]:

  #include <type_traits>

  template< bool isFriend >
  class Tester {
   public:
     template< typename T, typename = void >
     struct IsAccessible : public std::false_type {};

     template< typename T >
     struct IsAccessible< T, decltype( std::declval< T >().f() ) > : public
std::true_type {};
  };

  class Foo {
     friend Tester< true >;
     void f() const;
  };

  static_assert( !Tester< false >::IsAccessible< Foo >::value );
  static_assert( Tester< true >::IsAccessible< Foo >::value );

the first static_assert fails (with clang trunk), even though Tester< false >
isn't a friend of Foo, and therefore the partial specialization of IsAccessible
shouldn't be used for Tester< false >::IsAccessible< Foo >.

Note that this program works correctly in g++ (trunk), MSVC and ICC.</pre>
        </div>
      </p>


      <hr>
      <span>You are receiving this mail because:</span>

      <ul>
          <li>You are on the CC list for the bug.</li>
      </ul>
    </body>
</html>