syntax_data: {"ast_node_type":"other","tokens":[{"end":73,"kind":"keyword","start":0,"text":"ty::DebruijnIndex,"}]}
source_snippet:         ty::DebruijnIndex,         // Index corresponding to binder level
context_before:         Option<ty::DebruijnIndex>, // Debruijn index of the folded late-bound region
context_after:         ty::BoundRegion,