syntax_data: {"ast_node_type":"other","tokens":[{"end":43,"kind":"keyword","start":0,"text":"Self::Byte(b)"}]}
source_snippet:             Self::Byte(b) => Tree::Byte(b),
context_before:                 .fold(Tree::uninhabited(), |alts, alt| alts.or(alt)),
context_after:             Self::Ref(r) => Tree::Ref(r),