<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 --- - clang-cl fails to compile atlctrlw.h header from WTL"
   href="https://llvm.org/bugs/show_bug.cgi?id=26738">26738</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>clang-cl fails to compile atlctrlw.h header from WTL
          </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>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>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>andreybokhanko@gmail.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>A small reproducer is:

class CCommandBarCtrlImpl {
public:
  enum { _nMaxMenuItemTextLength = 100 };
};

void foo(CCommandBarCtrlImpl *pT) {
  char szString[pT->_nMaxMenuItemTextLength] = { 0 };
}


$ clang-cl H:/aero.cpp -c
H:/aero.cpp(7,17) :  error: variable-sized object may not be initialized
  char szString[pT->_nMaxMenuItemTextLength] = { 0 };
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.


Both MS and GCC compilers compile the test fine:

$ cl H:/aero.cpp -c
Microsoft (R) C/C++ Optimizing Compiler Version 18.00.31101 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

aero.cpp

$ echo $?
0


This construct is used in atlctrlw.h header from Windows Template Library:
(<a href="https://sourceforge.net/p/wtl/code/HEAD/tree/trunk/wtl/Include/atlctrlw.h#l1309">https://sourceforge.net/p/wtl/code/HEAD/tree/trunk/wtl/Include/atlctrlw.h#l1309</a>):

TCHAR szString[pT->_nMaxMenuItemTextLength] = { 0 };

nMaxMenuItemTextLength is defined at line 239 of the same header:

enum
{
        _nMaxMenuItemTextLength = 100,
        _chChevronShortcut = _T('/')
};

Yours,
Andrey
======
Software Engineer
Intel Compiler Team</pre>
        </div>
      </p>
      <hr>
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      <ul>
          <li>You are on the CC list for the bug.</li>
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