diff --git a/builder.go b/builder.go
index 18a2512..dcb551d 100644
--- a/builder.go
+++ b/builder.go
@@ -64,10 +64,6 @@ type StateDiffBuilder struct {
 	subtrieWorkers int
 }
 
-type iterPair struct {
-	Older, Newer trie.NodeIterator
-}
-
 type accountUpdate struct {
 	new     sdtypes.AccountWrapper
 	oldRoot common.Hash