diff --git a/util/proto/marshal.go b/util/proto/marshal.go
index 7bc8162..e345492 100644
--- a/util/proto/marshal.go
+++ b/util/proto/marshal.go
@@ -255,7 +255,7 @@ func NestedStructurePrefix(field int64) (prefix uint64, ln int) {
 	return prefix, VarUIntSize(prefix)
 }
 
-func NestedStructureMarshal(field int64, buf []byte, v stableMarshaller) int {
+func NestedStructureMarshal[T stableMarshaller](field int64, buf []byte, v T) int {
 	n := v.StableSize()
 	if n == 0 {
 		return 0
@@ -269,7 +269,7 @@ func NestedStructureMarshal(field int64, buf []byte, v stableMarshaller) int {
 	return offset + n
 }
 
-func NestedStructureSize(field int64, v stableMarshaller) (size int) {
+func NestedStructureSize[T stableMarshaller](field int64, v T) (size int) {
 	n := v.StableSize()
 	if n == 0 {
 		return 0