{"ast_node_type":"import","tokens":[{"end":106,"kind":"keyword","start":0,"text":"//"}]}
                // masking off any extra bits that occur because we did the arithmetic with too many bits.
                // The easiest way to do that is to do wrapping arithmetic on `u128` and then
                let niche_value = variant_index.as_u32() - niche_variants.start().as_u32();