{"ast_node_type":"variable","tokens":[{"end":59,"kind":"keyword","start":0,"text":"let"}]}
                    let kind = TyKind::Tup(ThinVec::new());
                    // We want to return std::hint::black_box(()).
                    let ty = P(rustc_ast::Ty { kind, id: ast::DUMMY_NODE_ID, span, tokens: None });