{"ast_node_type":"other","tokens":[{"end":57,"kind":"keyword","start":0,"text":"Pair(Either<V,"}]}
    Pair(Either<V, abi::Scalar>, Either<V, abi::Scalar>),
    Immediate(Either<V, abi::Scalar>),
    /// `repr(simd)` types need special handling because they each have a non-empty