syntax_data: {"ast_node_type":"other","tokens":[{"end":50,"kind":"keyword","start":0,"text":"TyKind::Error(_)"}]}
source_snippet:             TyKind::Error(_) => ty::List::empty(),
context_before:         match tupled_tys.kind() {
context_after:             TyKind::Tuple(..) => self.tupled_upvars_ty().tuple_fields(),