diff --git a/cpp/tests/neighbors/ann_ivf_flat.cuh b/cpp/tests/neighbors/ann_ivf_flat.cuh
index ccd7e2a253..13a3506188 100644
--- a/cpp/tests/neighbors/ann_ivf_flat.cuh
+++ b/cpp/tests/neighbors/ann_ivf_flat.cuh
@@ -307,14 +307,14 @@ class AnnIVFFlatTest : public ::testing::TestWithParam<AnnIvfFlatInputs<IdxT>> {
         auto& list_inds           = extend_index.lists()[label]->indices;
 
         // fetch the flat codes
-        auto flat_codes = raft::make_device_matrix<DataT, uint32_t>(handle_, list_size, idx.dim());
+        auto flat_codes = raft::make_device_matrix<DataT, int32_t>(handle_, list_size, idx.dim());
 
         raft::matrix::gather(
           handle_,
-          raft::make_device_matrix_view<const DataT, uint32_t>(
-            (const DataT*)database.data(), static_cast<uint32_t>(ps.num_db_vecs), idx.dim()),
-          raft::make_device_vector_view<const IdxT, uint32_t>((const IdxT*)list_inds.data_handle(),
-                                                              list_size),
+          raft::make_device_matrix_view<const DataT, int32_t>(
+            (const DataT*)database.data(), static_cast<int32_t>(ps.num_db_vecs), idx.dim()),
+          raft::make_device_vector_view<const IdxT, int32_t>((const IdxT*)list_inds.data_handle(),
+                                                             list_size),
           flat_codes.view());
 
         helpers::codepacker::pack(