syntax_data: {"ast_node_type":"other","tokens":[{"end":55,"kind":"keyword","start":0,"text":"local_expn_hashes:"}]}
source_snippet:     local_expn_hashes: IndexVec<LocalExpnId, ExpnHash>,
context_before:     local_expn_data: IndexVec<LocalExpnId, Option<ExpnData>>,
context_after:     /// Data and hash information from external crates. We may eventually want to remove these