{"ast_node_type":"variable","tokens":[{"end":91,"kind":"keyword","start":0,"text":"let"}]}
                let niche_value = variant_index.as_u32() - niche_variants.start().as_u32();
                let niche_type = fx.clif_type(niche.layout().ty).unwrap();
                let niche_value = (niche_value as u128).wrapping_add(niche_start);