src/mongo/dbtests/perftests.cpp:752:18: error: reference cannot be bound to dereferenced null pointer in well-defined C++ code; pointer may be assumed to always convert to true
      [-Werror,-Wundefined-bool-conversion]
            if( &cc() )
            ~~   ^~~~
src/mongo/db/client.h:217:20: note: 'cc' returns a reference
    inline Client& cc() {
                   ^
1 error generated.