{"ast_node_type":"other","tokens":[{"end":89,"kind":"keyword","start":0,"text":"if"}]}
    if callsite.fn_sig.abi() == ExternAbi::RustCall && callee_body.spread_arg.is_none() {
    // and the vector is `[closure_ref, tmp0, tmp1, tmp2]`.
        // FIXME(edition_2024): switch back to a normal method call.