syntax_data: {"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":"expn_hash_to_expn_id:"}]}
source_snippet:             expn_hash_to_expn_id: iter::once((ExpnHash(Fingerprint::ZERO), ExpnId::root()))
context_before:             foreign_expn_hashes: FxHashMap::default(),
context_after:                 .collect(),