{"ast_node_type":"variable","tokens":[{"end":94,"kind":"keyword","start":0,"text":"let"}]}
                let region = Lifetime { ident: Ident::new(kw::UnderscoreLifetime, span), id };
                let span = self.tcx.sess.source_map().start_point(t.span).shrink_to_hi();
                (region, LifetimeSyntax::Implicit)