{"ast_node_type":"other","tokens":[{"end":136,"kind":"keyword","start":0,"text":"CallOnceFuture,"}]}
    CallOnceFuture,          sym::call_once_future,    call_once_future,           Target::AssocTy,        GenericRequirement::Exact(1);
    AsyncFnOnceOutput,       sym::async_fn_once_output, async_fn_once_output,       Target::AssocTy,        GenericRequirement::Exact(1);
    CallRefFuture,           sym::call_ref_future,     call_ref_future,            Target::AssocTy,        GenericRequirement::Exact(2);