<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 - Duplicated warning message in -Wcomma"
   href="https://bugs.llvm.org/show_bug.cgi?id=46438">46438</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Duplicated warning message in -Wcomma
          </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>Frontend
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>haoxintu@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>This code, bug.cc, clang-9 to clang-trunk emit two duplicated warning message
"warning: possible misuse of comma operator here [-Wcomma]", while clang-6 to
clang-8 just give one warning message about this.

$cat bug.cc
const long var = 10;
static_assert (1 ? ( 0 , var ) : 0 , "" );

$clang++-trunk -Wcomma -c bug.cc 
bug.cc:2:24: warning: possible misuse of comma operator here [-Wcomma]
static_assert (1 ? ( 0 , var ) : 0 , "" );
                       ^
bug.cc:2:22: note: cast expression to void to silence warning
static_assert (1 ? ( 0 , var ) : 0 , "" );
                     ^
                     static_cast<void>( )
bug.cc:2:24: warning: possible misuse of comma operator here [-Wcomma]
static_assert (1 ? ( 0 , var ) : 0 , "" );
                       ^
bug.cc:2:22: note: cast expression to void to silence warning
static_assert (1 ? ( 0 , var ) : 0 , "" );
                     ^
                     static_cast<void>( )
2 warnings generated.


$clang++-8 -Wcomma -c bug.cc 
bug.cc:2:24: warning: possible misuse of comma operator here [-Wcomma]
static_assert (1 ? ( 0 , var ) : 0 , "" );
                       ^
bug.cc:2:22: note: cast expression to void to silence warning
static_assert (1 ? ( 0 , var ) : 0 , "" );
                     ^
                     static_cast<void>( )
1 warning generated.</pre>
        </div>
      </p>


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