syntax_data: {"ast_node_type":"other","tokens":[{"end":58,"kind":"keyword","start":0,"text":"UpvarArgs::CoroutineClosure(args)"}]}
source_snippet:                     UpvarArgs::CoroutineClosure(args) => {
context_before:                     }
context_after:                         Box::new(AggregateKind::CoroutineClosure(closure_id.to_def_id(), args))