{"ast_node_type":"impl","tokens":[{"end":20,"kind":"keyword","start":0,"text":"\"impl"}]}
        "impl item";
    TraitImplItems(SmallVec<[P<ast::AssocItem>; 1]>) {
        many fn flat_map_assoc_item; fn visit_assoc_item(AssocCtxt::Impl { of_trait: true });