syntax_data: {"ast_node_type":"other","tokens":[{"end":86,"kind":"keyword","start":0,"text":"VariantIdx::from(CoroutineArgs::RESERVED_VARIANTS"}]}
source_snippet:             VariantIdx::from(CoroutineArgs::RESERVED_VARIANTS + suspension_point_idx);
context_before:         let variant_index =
context_after:         let mut fields = IndexVec::new();