trie: add difference iterator (#3637)

This PR implements a differenceIterator, which allows iterating over trie nodes
that exist in one trie but not in another. This is a prerequisite for most GC
strategies, in order to find obsolete nodes.

1 files changed, 1 insertions, 1 deletions

diff --git a/trie/secure_trie.go b/trie/secure_trie.go
index 4d9ebe4d3..8b90da02f 100644
--- a/trie/secure_trie.go
+++ b/trie/secure_trie.go
@@ -159,7 +159,7 @@ func (t *SecureTrie) Iterator() *Iterator {
 	return t.trie.Iterator()
 }
 
-func (t *SecureTrie) NodeIterator() *NodeIterator {
+func (t *SecureTrie) NodeIterator() NodeIterator {
 	return NewNodeIterator(&t.trie)
 }