At least on non-Avian runtimes. :-) https://github.com/soc/scala/commit/98e57a2391a8219660b7f92a7b235a7401794755#L1L278

I think I'll need to explicitly add some option so that it doesn't take the `true` branch on Avian.
Can you suggest a better name? Maybe just `case "not-avian"  => !isAvian`...