syntax_data: {"ast_node_type":"function","tokens":[{"end":95,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn renumber_bitset(&self, input: &DenseBitSet<Local>) -> DenseBitSet<CoroutineSavedLocal> {
context_before:     /// equivalent `DenseBitSet<CoroutineSavedLocal>`.
context_after:         assert!(self.superset(input), "{:?} not a superset of {:?}", self.0, input);