diff --git a/src/hnswutils.c b/src/hnswutils.c
index e082808..6d2cf4f 100644
--- a/src/hnswutils.c
+++ b/src/hnswutils.c
@@ -163,9 +163,9 @@ HnswGetType(Relation index)
 	Oid			typid = TupleDescAttr(index->rd_att, 0)->atttypid;
 	HeapTuple	tuple;
 	Form_pg_type type;
-	int			result;
+	HnswType	result;
 
-	if (typid == BITOID || typid == VARBITOID)
+	if (typid == BITOID)
 		return HNSW_TYPE_BIT;
 
 	tuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
@@ -180,7 +180,10 @@ HnswGetType(Relation index)
 	else if (strcmp(NameStr(type->typname), "sparsevec") == 0)
 		result = HNSW_TYPE_SPARSEVEC;
 	else
-		elog(ERROR, "Unsupported type");
+	{
+		ReleaseSysCache(tuple);
+		elog(ERROR, "type not supported for hnsw index");
+	}
 
 	ReleaseSysCache(tuple);
 
diff --git a/test/expected/hnsw_bit_hamming.out b/test/expected/hnsw_bit_hamming.out
index 0483281..bda949e 100644
--- a/test/expected/hnsw_bit_hamming.out
+++ b/test/expected/hnsw_bit_hamming.out
@@ -19,3 +19,9 @@ SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <~> (SELECT NULL::bit)) t2;
 (1 row)
 
 DROP TABLE t;
+-- TODO move
+CREATE TABLE t (val varbit(3));
+CREATE INDEX ON t USING hnsw (val bit_hamming_ops);
+ERROR:  type not supported for hnsw index
+CREATE INDEX ON t USING hnsw ((val::bit(3)) bit_hamming_ops);
+DROP TABLE t;
diff --git a/test/sql/hnsw_bit_hamming.sql b/test/sql/hnsw_bit_hamming.sql
index fb21511..5319461 100644
--- a/test/sql/hnsw_bit_hamming.sql
+++ b/test/sql/hnsw_bit_hamming.sql
@@ -10,3 +10,9 @@ SELECT * FROM t ORDER BY val <~> B'111';
 SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <~> (SELECT NULL::bit)) t2;
 
 DROP TABLE t;
+
+-- TODO move
+CREATE TABLE t (val varbit(3));
+CREATE INDEX ON t USING hnsw (val bit_hamming_ops);
+CREATE INDEX ON t USING hnsw ((val::bit(3)) bit_hamming_ops);
+DROP TABLE t;