<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 --- - [MS] Clang mangles lambdas in member initializers incorrectly"
   href="https://llvm.org/bugs/show_bug.cgi?id=31197">31197</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>[MS] Clang mangles lambdas in member initializers incorrectly
          </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>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>LLVM Codegen
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>rnk@google.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Consider:

struct A {
  int x = []() { return 1; }();
  int y = []() { return 2; }();
};
int main() {
  A a;
  return a.x + a.y;
}

Clang optimizes this program to return 2 on Windows, because both lambdas use
the mangling context of the expression evaluation contexts of 'x' and 'y'
respectively.

This is underlying cause of the current Windows build failures in
ToolingTest.cpp:

<a href="http://lab.llvm.org:8011/builders/clang-x86-windows-msvc2015/builds/846">http://lab.llvm.org:8011/builders/clang-x86-windows-msvc2015/builds/846</a>

C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\xutility(285,3):
 error: definition with same mangled name as another definition
                _Compressed_pair(_One_then_variadic_args_t,
                ^
C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\xutility(285,3):
 note: previous definition is here
C:\Program Files (x86)\Microsoft Visual Studio
14.0\VC\INCLUDE\xutility(298,14):  error: definition with same mangled name as
another definition
        const _Ty1& _Get_first() const _NOEXCEPT</pre>
        </div>
      </p>
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