syntax_data: {"ast_node_type":"other","tokens":[{"end":94,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// Data and hash information from external crates. We may eventually want to remove these
context_before:     local_expn_hashes: IndexVec<LocalExpnId, ExpnHash>,
context_after:     /// maps, and fetch the information directly from the other crate's metadata like DefIds do.