diff --git a/src/metric/auc.cu b/src/metric/auc.cu
index 2091fe148..7f57d1a87 100644
--- a/src/metric/auc.cu
+++ b/src/metric/auc.cu
@@ -19,9 +19,6 @@
 namespace xgboost {
 namespace metric {
 namespace {
-template <typename T>
-using Discard = thrust::discard_iterator<T>;
-
 struct GetWeightOp {
   common::Span<float const> weights;
   common::Span<size_t const> sorted_idx;
diff --git a/src/tree/updater_gpu_hist.cu b/src/tree/updater_gpu_hist.cu
index 1014bf53a..382469194 100644
--- a/src/tree/updater_gpu_hist.cu
+++ b/src/tree/updater_gpu_hist.cu
@@ -181,8 +181,6 @@ struct GPUHistMakerDevice {
 
   dh::PinnedMemory pinned;
 
-  std::vector<cudaStream_t> streams{};
-
   common::Monitor monitor;
   TreeEvaluator tree_evaluator;
   common::ColumnSampler column_sampler;
@@ -228,9 +226,6 @@ struct GPUHistMakerDevice {
 
   ~GPUHistMakerDevice() {  // NOLINT
     dh::safe_cuda(cudaSetDevice(device_id));
-    for (auto& stream : streams) {
-      dh::safe_cuda(cudaStreamDestroy(stream));
-    }
   }
 
   // Reset values for each update iteration