syntax_data: {"ast_node_type":"other","tokens":[{"end":45,"kind":"keyword","start":0,"text":"Interned($span4:ident)"}]}
source_snippet:         Interned($span4:ident) => $arm4:expr,
context_before:         PartiallyInterned($span3:ident) => $arm3:expr,
context_after:     ) => {