syntax_data: {"ast_node_type":"variable","tokens":[{"end":48,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let rvalue = match self.coroutine_kind {
context_before:         const ONE: VariantIdx = VariantIdx::from_usize(1);
context_after:             CoroutineKind::Desugared(CoroutineDesugaring::Async, _) => {