<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 - incompatible declaration"
   href="https://bugs.llvm.org/show_bug.cgi?id=42244">42244</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>incompatible declaration
          </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>zhonghao@pku.org.cn
          </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 is 9.0.0, and my code is as follows:

template<int...> struct A
{
  void foo();
};

struct B
{
  template<int N> friend void A<N>::A::foo();
};

clang accepts the code. gcc rejects it:

source>:7:44: error: member 'void typename A<N>::A::foo()' declared as friend
before type 'typename A<N>::A' defined

    7 |   template<int N> friend void A<N>::A::foo();

      |                                            ^

Compiler returned: 1

icc also rejects it:

<source>(7): error: declaration is incompatible with nontype "<unnamed>
A<N>::A::foo" (declared at line 7)

    template<int N> friend void A<N>::A::foo();

                                         ^

compilation aborted for <source> (code 2)

Compiler returned: 2</pre>
        </div>
      </p>


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