Clang 3.5 reports error: 'this' pointer cannot be null in well defined C++

In file included from src/mongo/client/dbclientinterface.h:1388:

src/mongo/client/dbclientcursor.h:122:40: error: 'this' pointer cannot be null in well-defined C++ code; pointer may

      be assumed to always convert to true [-Werror,-Wundefined-bool-conversion]

        bool isDead() const { return  !this || cursorId == 0; }