<html>
    <head>
      <base href="https://llvm.org/bugs/" />
    </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 --- - Should NamedDecl::declarationReplaces consider friend status?"
   href="https://llvm.org/bugs/show_bug.cgi?id=30994">30994</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Should NamedDecl::declarationReplaces consider friend status?
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>new-bugs
          </td>
        </tr>

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

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

        <tr>
          <th>OS</th>
          <td>Windows NT
          </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>new bugs
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>yaron.keren@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk, vvasilev@cern.ch
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Given the code

namespace boost {
template <class> class shared_ptr { 
  template <class> friend class shared_ptr;
};
}

shared_ptr<char> c;
shared_ptr<int> i;

shared_ptr<char> is created with its TemplateDecl being the class shared_ptr
while shared_ptr<int> TemplateDecl is the friend TemplateDecl created in
shared_ptr<char>.

This happens because the friend TemplateDecl created in shared_ptr<char>
replaces the original class TemplateDecl.

It seems inconsistent that both ClassTemplateSpecializationDecl have different
TemplateDecl.

To solve this, we could demand same friendness in
NamedDecl::declarationReplaces

bool NamedDecl::declarationReplaces(NamedDecl *OldD, bool IsKnownNewer) const {
...
  // Friend should not replace non-friend.
  if (OldD->getFriendObjectKind() != getFriendObjectKind())
    return false;</pre>
        </div>
      </p>
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