{"ast_node_type":"variable","tokens":[{"end":42,"kind":"keyword","start":0,"text":"let"}]}
    let mut alt_self_params = self_params;
    let s_ty = cx.ty_ident(span, Ident::new(sym::__S, span));
    alt_self_params[pointee_param_idx] = GenericArg::Type(s_ty.clone());