{"ast_node_type":"variable","tokens":[{"end":41,"kind":"keyword","start":0,"text":"let"}]}
    let decl = cx.fn_decl(params, never);
    let params = thin_vec![cx.param(span, size, ty_usize.clone()), cx.param(span, align, ty_usize)];
    let header = FnHeader { safety: Safety::Unsafe(span), ..FnHeader::default() };