return nsPromiseCConcatenation(lhs, rhs, lhs.GetFragmentIdentifierMask()<<1);
return nsDependentConcatenation(lhs, rhs, lhs.GetFragmentIdentifierMask()<<1);
operator+( const nsPromiseCConcatenation& lhs, const nsACString& rhs )  {    return nsPromiseCConcatenation(lhs, rhs, lhs.GetFragmentIdentifierMask()<<1);  }