{"ast_node_type":"other","tokens":[{"end":55,"kind":"keyword","start":0,"text":".map(|def_id|"}]}
        .map(|def_id| make_dummy_instance(tcx, def_id))
        .filter(|&def_id| is_unused_fn(def_id))
        .map(|instance| UnusedInstance { instance, symbol_name: tcx.symbol_name(instance) })