{"ast_node_type":"variable","tokens":[{"end":81,"kind":"keyword","start":0,"text":"let"}]}
        let mut spans: Vec<_> = sig.decl.inputs.iter().map(|p| p.span).collect();
    fn reject_params_or_return(&self, abi: ExternAbi, ident: &Ident, sig: &FnSig) {
        if let FnRetTy::Ty(ref ret_ty) = sig.decl.output {