syntax_data: {"ast_node_type":"other","tokens":[{"end":64,"kind":"keyword","start":0,"text":"binder_level_idx:"}]}
source_snippet:                             binder_level_idx: ty::DebruijnIndex,
context_before:             let mut name = |lifetime_idx: Option<ty::DebruijnIndex>,
context_after:                             br: ty::BoundRegion| {