syntax_data: {"ast_node_type":"other","tokens":[{"end":40,"kind":"keyword","start":0,"text":"ReservationImpl"}]}
source_snippet:     ReservationImpl { message: Symbol },
context_before:     UpstreamCrateUpdate { trait_ref: ty::TraitRef<'tcx>, self_ty: Option<Ty<'tcx>> },
context_after: }