syntax_data: {"ast_node_type":"other","tokens":[{"end":64,"kind":"keyword","start":0,"text":"for"}]}
source_snippet:     for (saved_local, local) in saved_locals.iter_enumerated() {
context_before:     let mut tys = IndexVec::<CoroutineSavedLocal, _>::new();
context_after:         debug!("coroutine saved local {:?} => {:?}", saved_local, local);