boolean (@NotNull DfType other) { if (!isSuperType(other)) return false; if (getNullability() == DfaNullability.UNKNOWN || getNullability() == DfaNullability.FLUSHED) { DfaNullability otherNullability = DfaNullability.fromDfType(other); return otherNullability != DfaNullability.NULL && otherNullability != DfaNullability.NULLABLE; } return true; }