syntax_data: {"ast_node_type":"other","tokens":[{"end":71,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// Used to force two `ExpnData`s to have different `Fingerprint`s.
context_before:     pub call_site: Span,
context_after:     /// Due to macro expansion, it's possible to end up with two `ExpnId`s