PVS-Studio warning V530 for TortoiseSVN

CMailMsg& CMailMsg::SetFrom(string sAddress,
                            string sName)
{
   if (initIfNeeded())
   {
      // only one sender allowed
      if (m_from.size())
         m_from.empty();
      m_from.push_back(TStrStrPair(sAddress,sName));
   }
   return *this;
}

This is what should have been written here: m_from.clear();

This suspicious code was found in TortoiseSVN project by PVS-Studio static code analyzer.
Warning message is:
V530 The return value of function 'empty' is required to be utilized. mailmsg.cpp 40

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/