syntax_data: {"ast_node_type":"function","tokens":[{"end":82,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn expected_state_at_target(&self, target: SeekTarget) -> DenseBitSet<usize> {
context_before:     /// would be `[102, 0, 1, 2, 3, 4]`.
context_after:         let block = target.block();