i know from past vellum optimization work that this call, in particular, is pretty expensive and can have performance issues (not sure if that's since been optimized).

we really don't have a simpler way to determine parent type that doesn't entail walking the entire tree?

(it probably doesn't matter if this only gets called once, but if it gets called, e.g. every time you do some frequent operation we may want to remember it as a source of future slowness)