syntax_data: {"ast_node_type":"variable","tokens":[{"end":60,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let mut tys = IndexVec::<CoroutineSavedLocal, _>::new();
context_before:     let mut locals = IndexVec::<CoroutineSavedLocal, _>::new();
context_after:     for (saved_local, local) in saved_locals.iter_enumerated() {