syntax_data: {"ast_node_type":"other","tokens":[{"end":49,"kind":"keyword","start":0,"text":"ty::Never"}]}
source_snippet:         ty::Never => Some(SimplifiedType::Never),
context_before:         ty::CoroutineWitness(def_id, _) => Some(SimplifiedType::CoroutineWitness(def_id)),
context_after:         ty::Tuple(tys) => Some(SimplifiedType::Tuple(tys.len())),