syntax_data: {"ast_node_type":"other","tokens":[{"end":86,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // expression, exhaustiveness checking ensures that this block is unreachable.
context_before:         // If none of the arms match, we branch to `otherwise_block`. When lowering a `match`
context_after:         let mut candidate_refs = candidates.iter_mut().collect::<Vec<_>>();