diff --git a/lib/dnsbox-derive/src/dns_packet_data.rs b/lib/dnsbox-derive/src/dns_packet_data.rs
index dcd07cf..02754f4 100644
--- a/lib/dnsbox-derive/src/dns_packet_data.rs
+++ b/lib/dnsbox-derive/src/dns_packet_data.rs
@@ -54,6 +54,7 @@ fn derive_unnamed(s: &synstructure::Structure, fields: &syn::FieldsUnnamed) -> T
 	let mut parse_fields = quote!{};
 	let mut serialize_fields = quote!{};
 	for field in 0..fields.unnamed.len() {
+		let field = syn::Index::from(field);
 		parse_fields.extend(quote!{
 			DnsPacketData::deserialize(_data)
 				.with_context(|e| format!("failed parsing field {}::{}: {}", stringify!(#name), #field, e))?,
diff --git a/lib/dnsbox-derive/src/dns_text_data.rs b/lib/dnsbox-derive/src/dns_text_data.rs
index dad620a..83f3b35 100644
--- a/lib/dnsbox-derive/src/dns_text_data.rs
+++ b/lib/dnsbox-derive/src/dns_text_data.rs
@@ -53,6 +53,7 @@ fn derive_unnamed(s: &synstructure::Structure, fields: &syn::FieldsUnnamed) -> T
 	let mut parse_fields = quote!{};
 	let mut format_fields = quote!{};
 	for field in 0..fields.unnamed.len() {
+		let field = syn::Index::from(field);
 		parse_fields.extend(quote!{
 			DnsTextData::dns_parse(_context, _data)
 				.with_context(|e| format!("failed parsing field {}::{}: {}", stringify!(#name), #field, e))?,