syntax_data: {"ast_node_type":"variable","tokens":[{"end":41,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let mut fields = IndexVec::new();
context_before:             VariantIdx::from(CoroutineArgs::RESERVED_VARIANTS + suspension_point_idx);
context_after:         for (idx, saved_local) in live_locals.iter().enumerate() {