qt-everywhere-src-5.11.3/qtbase/src/corelib/codecs/qwindowscodec.cpp:182: bad error checking ?

size_t size = mbstowcs(NULL, mb, length);
 if (size < 0) {
 Q_ASSERT("Error in CE TextCodec");
 return QString();
 }

size_t size = mbstowcs(NULL, mb, length);
 if (size == (size_t) -1) {
 Q_ASSERT("Error in CE TextCodec");
 return QString();
 }