{"ast_node_type":"other","tokens":[{"end":80,"kind":"keyword","start":0,"text":"BackendRepr::Scalar(_)"}]}
                    BackendRepr::Scalar(_) => BackendRepr::Scalar(niche_scalar),
                    // same ABI as the scalar variant with the reserved niche.
                    BackendRepr::ScalarPair(first, second) => {