syntax_data: {"ast_node_type":"other","tokens":[{"end":49,"kind":"keyword","start":0,"text":"impl<T:"}]}
source_snippet: impl<T: Idx> JoinSemiLattice for DenseBitSet<T> {
context_before: /// for each possible value of `T`.
context_after:     fn join(&mut self, other: &Self) -> bool {