{"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"(\"a\","}]}
                ("a", "Result", "Err", ret_ty_matches(sym::Result))
            if self.tcx.is_diagnostic_item(sym::Result, adt.did()) {
            } else if self.tcx.is_diagnostic_item(sym::Option, adt.did()) {