syntax_data: {"ast_node_type":"other","tokens":[{"end":77,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// - FIXME: We sometimes don't unset this when clearing `subcandidates`.
context_before:     /// Invariant: it is `None` iff `subcandidates.is_empty()`.
context_after:     or_span: Option<Span>,