diff --git a/test/expected/cast.out b/test/expected/cast.out
index c180fe6..9087653 100644
--- a/test/expected/cast.out
+++ b/test/expected/cast.out
@@ -268,6 +268,8 @@ SELECT array_agg(n)::vector FROM generate_series(1, 16001) n;
 ERROR:  vector cannot have more than 16000 dimensions
 SELECT array_to_vector(array_agg(n), 16001, false) FROM generate_series(1, 16001) n;
 ERROR:  vector cannot have more than 16000 dimensions
+SELECT array_agg(n)::halfvec FROM generate_series(1, 16001) n;
+ERROR:  halfvec cannot have more than 16000 dimensions
 -- ensure no error
 SELECT ARRAY[1,2,3] = ARRAY[1,2,3];
  ?column? 
diff --git a/test/sql/cast.sql b/test/sql/cast.sql
index fe83931..c35799e 100644
--- a/test/sql/cast.sql
+++ b/test/sql/cast.sql
@@ -76,6 +76,7 @@ SELECT '{{1}}'::real[]::sparsevec;
 
 SELECT array_agg(n)::vector FROM generate_series(1, 16001) n;
 SELECT array_to_vector(array_agg(n), 16001, false) FROM generate_series(1, 16001) n;
+SELECT array_agg(n)::halfvec FROM generate_series(1, 16001) n;
 
 -- ensure no error
 SELECT ARRAY[1,2,3] = ARRAY[1,2,3];