diff --git a/core/state/snapshot/conversion.go b/core/state/snapshot/conversion.go
index 681be7ebc0..12ec6c398e 100644
--- a/core/state/snapshot/conversion.go
+++ b/core/state/snapshot/conversion.go
@@ -43,7 +43,7 @@ type trieKV struct {
 type (
 	// trieGeneratorFn is the interface of trie generation which can
 	// be implemented by different trie algorithm.
-	trieGeneratorFn func(db ethdb.KeyValueWriter, scheme string, owner common.Hash, in chan (trieKV), out chan (common.Hash))
+	trieGeneratorFn func(db ethdb.KeyValueWriter, scheme string, owner common.Hash, in chan trieKV, out chan common.Hash)
 
 	// leafCallbackFn is the callback invoked at the leaves of the trie,
 	// returns the subtrie root with the specified subtrie identifier.