syntax_data: {"ast_node_type":"other","tokens":[{"end":26,"kind":"keyword","start":0,"text":"false"}]}
source_snippet:                 false => {
context_before:                 true => exported_impl_order[&impl_def_id] as u64,
context_after:                     exported_impl_order.len() as u64 + key.disambiguated_data.disambiguator as u64