trie/bintrie: use type alias for HashedNode

Replace the single-field struct with a type alias on common.Hash.
Both have identical layout (32 bytes, no pointers) and noscan span
placement, but the alias matches master's style and reads more
naturally. A zero-arg Hash() method keeps call sites terse.

trie/bintrie/hashed_node.go

@@ -18,7 +18,8 @@ package bintrie
 
 import "github.com/ethereum/go-ethereum/common"
 
-// HashedNode is an unresolved node (hash only).
+// HashedNode is an unresolved node — only its hash is known.
-type HashedNode struct {
+type HashedNode common.Hash
-	hash common.Hash
+
-}
+// Hash returns the node's hash.
+func (h HashedNode) Hash() common.Hash { return common.Hash(h) }

trie/bintrie/iterator.go

@@ -126,12 +126,12 @@ func (it *binaryNodeIterator) Next(descend bool) bool {
 			return false
 		}
 		hn := it.store.getHashed(it.current.Index())
-		data, err := it.trie.nodeResolver(it.Path(), hn.hash)
+		data, err := it.trie.nodeResolver(it.Path(), hn.Hash())
 		if err != nil {
 			it.lastErr = err
 			return false
 		}
-		resolved, err := it.store.DeserializeNodeWithHash(data, len(it.stack)-1, hn.hash)
+		resolved, err := it.store.DeserializeNodeWithHash(data, len(it.stack)-1, hn.Hash())
 		if err != nil {
 			it.lastErr = err
 			return false

trie/bintrie/node_store.go

@@ -151,7 +151,7 @@ func (s *NodeStore) freeHashedNode(idx uint32) {
 
 func (s *NodeStore) newHashedRef(hash common.Hash) NodeRef {
 	idx := s.allocHashed()
-	*s.getHashed(idx) = HashedNode{hash: hash}
+	*s.getHashed(idx) = HashedNode(hash)
 	return MakeRef(KindHashed, idx)
 }
 

trie/bintrie/store_commit.go

@@ -38,7 +38,7 @@ func (s *NodeStore) ComputeHash(ref NodeRef) common.Hash {
 	case KindStem:
 		return s.getStem(ref.Index()).Hash()
 	case KindHashed:
-		return s.getHashed(ref.Index()).hash
+		return s.getHashed(ref.Index()).Hash()
 	case KindEmpty:
 		return common.Hash{}
 	default:
@@ -259,7 +259,7 @@ func (s *NodeStore) ToDot(ref NodeRef, parent, path string) string {
 	case KindHashed:
 		hn := s.getHashed(ref.Index())
 		me := fmt.Sprintf("hash%s", path)
-		ret := fmt.Sprintf("%s [label=\"%x\"]\n", me, hn.hash)
+		ret := fmt.Sprintf("%s [label=\"%x\"]\n", me, hn.Hash())
 		ret = fmt.Sprintf("%s %s -> %s\n", ret, parent, me)
 		return ret
 	default:

trie/bintrie/store_ops.go

@@ -72,11 +72,11 @@ func (s *NodeStore) getSingle(ref NodeRef, stem []byte, suffix byte, resolver No
 			hn := s.getHashed(cur.Index())
 			parentNode := s.getInternal(parentIdx)
 			path := makeKeyPath(int(parentNode.depth), stem)
-			data, err := resolver(path, hn.hash)
+			data, err := resolver(path, hn.Hash())
 			if err != nil {
 				return nil, fmt.Errorf("getSingle resolve error: %w", err)
 			}
-			resolved, err := s.DeserializeNodeWithHash(data, int(parentNode.depth)+1, hn.hash)
+			resolved, err := s.DeserializeNodeWithHash(data, int(parentNode.depth)+1, hn.Hash())
 			if err != nil {
 				return nil, fmt.Errorf("getSingle deserialization error: %w", err)
 			}
@@ -143,11 +143,11 @@ func (s *NodeStore) getValuesAtStem(ref NodeRef, stem []byte, resolver NodeResol
 			hn := s.getHashed(cur.Index())
 			parentNode := s.getInternal(parentIdx)
 			path := makeKeyPath(int(parentNode.depth), stem)
-			data, err := resolver(path, hn.hash)
+			data, err := resolver(path, hn.Hash())
 			if err != nil {
 				return nil, fmt.Errorf("getValuesAtStem resolve error: %w", err)
 			}
-			resolved, err := s.DeserializeNodeWithHash(data, int(parentNode.depth)+1, hn.hash)
+			resolved, err := s.DeserializeNodeWithHash(data, int(parentNode.depth)+1, hn.Hash())
 			if err != nil {
 				return nil, fmt.Errorf("getValuesAtStem deserialization error: %w", err)
 			}
@@ -251,11 +251,11 @@ func (s *NodeStore) insertSingleInternal(stem []byte, suffix byte, value []byte,
 			parentNode := s.getInternal(p.internalIdx)
 			hn := s.getHashed(cur.Index())
 			path := makeKeyPath(int(parentNode.depth), stem)
-			data, err := resolver(path, hn.hash)
+			data, err := resolver(path, hn.Hash())
 			if err != nil {
 				return fmt.Errorf("insertSingle resolve error: %w", err)
 			}
-			resolved, err := s.DeserializeNodeWithHash(data, int(parentNode.depth)+1, hn.hash)
+			resolved, err := s.DeserializeNodeWithHash(data, int(parentNode.depth)+1, hn.Hash())
 			if err != nil {
 				return fmt.Errorf("insertSingle deserialization error: %w", err)
 			}
@@ -370,11 +370,11 @@ func (s *NodeStore) insertValuesAtStem(ref NodeRef, stem []byte, values [][]byte
 				}
 				hn := s.getHashed(node.left.Index())
 				path := makeKeyPath(int(node.depth), stem)
-				data, err := resolver(path, hn.hash)
+				data, err := resolver(path, hn.Hash())
 				if err != nil {
 					return ref, fmt.Errorf("InsertValuesAtStem resolve error: %w", err)
 				}
-				resolved, err := s.DeserializeNodeWithHash(data, int(node.depth)+1, hn.hash)
+				resolved, err := s.DeserializeNodeWithHash(data, int(node.depth)+1, hn.Hash())
 				if err != nil {
 					return ref, fmt.Errorf("InsertValuesAtStem deserialization error: %w", err)
 				}
@@ -393,11 +393,11 @@ func (s *NodeStore) insertValuesAtStem(ref NodeRef, stem []byte, values [][]byte
 				}
 				hn := s.getHashed(node.right.Index())
 				path := makeKeyPath(int(node.depth), stem)
-				data, err := resolver(path, hn.hash)
+				data, err := resolver(path, hn.Hash())
 				if err != nil {
 					return ref, fmt.Errorf("InsertValuesAtStem resolve error: %w", err)
 				}
-				resolved, err := s.DeserializeNodeWithHash(data, int(node.depth)+1, hn.hash)
+				resolved, err := s.DeserializeNodeWithHash(data, int(node.depth)+1, hn.Hash())
 				if err != nil {
 					return ref, fmt.Errorf("InsertValuesAtStem deserialization error: %w", err)
 				}
@@ -437,11 +437,11 @@ func (s *NodeStore) insertValuesAtStem(ref NodeRef, stem []byte, values [][]byte
 		if resolver == nil {
 			return ref, errors.New("InsertValuesAtStem: resolver is nil")
 		}
-		data, err := resolver(path, hn.hash)
+		data, err := resolver(path, hn.Hash())
 		if err != nil {
 			return ref, fmt.Errorf("InsertValuesAtStem resolve error: %w", err)
 		}
-		resolved, err := s.DeserializeNodeWithHash(data, depth, hn.hash)
+		resolved, err := s.DeserializeNodeWithHash(data, depth, hn.Hash())
 		if err != nil {
 			return ref, fmt.Errorf("InsertValuesAtStem deserialization error: %w", err)
 		}