syntax_data: {"ast_node_type":"other","tokens":[{"end":53,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // disambiguator at 0 (the default u32 value)
context_before:         // If this is the first ExpnData with a given hash, then keep our
context_after:         let disambig = data.expn_data_disambiguators.entry(expn_hash).or_default();