{"ast_node_type":"variable","tokens":[{"end":91,"kind":"keyword","start":0,"text":"let"}]}
        let header = FnHeader { safety: Safety::Unsafe(self.span), ..FnHeader::default() };
        let decl = self.cx.fn_decl(abi_args, ast::FnRetTy::Ty(output_ty));
        let sig = FnSig { decl, header, span: self.span };