syntax_data: {"ast_node_type":"other","tokens":[{"end":71,"kind":"keyword","start":0,"text":"//"}]}
source_snippet: // `SyntaxContext::outer_expn_data` combines `SyntaxContext::outer` and
context_before: // with a certain amount of redundancy in them. For example,
context_after: // `ExpnId::expn_data` so that two `HygieneData` accesses can be performed within