/// `u32::MAX`. You can also customize things like the `Debug` impl,
/// what traits are derived, and so forth via the macro.
#[proc_macro]
-#[allow_internal_unstable(step_trait, rustc_attrs, trusted_step)]
+#[allow_internal_unstable(step_trait, rustc_attrs, trusted_step, spec_option_partial_eq)]
pub fn newtype_index(input: TokenStream) -> TokenStream {
newtype::newtype(input)
}