PVS-Studio warning V530 for QuantLib

void CommodityCurve::setPrices(std::map<Date, Real>& prices) {
  QL_REQUIRE(prices.size()>1, "too few prices");

  dates_.empty();
  data_.empty();

  for (std::map<Date, Real>::const_iterator i = prices.begin();
       i != prices.end(); i++)
  {
    dates_.push_back(i->first);
    data_.push_back(i->second);
  }
  ....
}

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

This suspicious code was found in QuantLib project by PVS-Studio static code analyzer.
Warning message is:
V530 The return value of function 'empty' is required to be utilized. commoditycurve.cpp 70

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/