{"ast_node_type":"variable","tokens":[{"end":59,"kind":"keyword","start":0,"text":"if"}]}
            if let ty::Param(sig_param) = param_ty.kind() {
        for (i, &param_ty) in fn_sig.inputs().iter().enumerate() {
                // It is a type parameter. Check if it is `impl Into<{D,Subd}iagMessage>`.