syntax_data: {"ast_node_type":"function","tokens":[{"end":80,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn merge_trivial_subcandidates(&mut self, candidate: &mut Candidate<'tcx>) {
context_before:     /// in match tree lowering.
context_after:         assert!(!candidate.subcandidates.is_empty());