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      <base href="https://llvm.org/bugs/" />
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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 --- - Assertion failed: (isa<LabelDecl>(D) && "declaration not instantiated in this scope")"
   href="https://llvm.org/bugs/show_bug.cgi?id=23194">23194</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Assertion failed: (isa<LabelDecl>(D) && "declaration not instantiated in this scope")
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Macintosh
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </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>howard.hinnant@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Assertion failed: (isa<LabelDecl>(D) && "declaration not instantiated in this
scope"), function findInstantiationOf, file
/Users/howardhinnant/Development/llvm/tools/clang/lib/Sema/SemaTemplateInstantiate.cpp,
line 2802.

Here is a reduced case that comes from real-world code which causes this assert
in clang tip-of-trunk:

struct X
{
    int operator()() const {return 0;}
};

struct Y
{
    Y(int) {}
};

template <bool = true>
int
make_seed_pair() noexcept
{
    struct state_t
    {
        X x;
        Y y{x()};

    };
    return 0;
}

int
main()
{
    auto s = make_seed_pair();
}

Using this command line:

clang++ -std=c++11 test.cpp

This is a regression.  This compiler compiles this example ok:

Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin13.4.0
Thread model: posix</pre>
        </div>
      </p>
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