syntax_data: {"ast_node_type":"other","tokens":[{"end":72,"kind":"keyword","start":0,"text":"TyKind::Tuple(..)"}]}
source_snippet:             TyKind::Tuple(..) => self.tupled_upvars_ty().tuple_fields(),
context_before:             TyKind::Error(_) => ty::List::empty(),
context_after:             TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"),