diff --git a/src/tree/updater_quantile_hist.h b/src/tree/updater_quantile_hist.h
index 95d13d7b56df..4213d5dc8862 100644
--- a/src/tree/updater_quantile_hist.h
+++ b/src/tree/updater_quantile_hist.h
@@ -91,7 +91,7 @@ class HistRowPartitioner {
   /**
    * \brief Turn split values into discrete bin indices.
    */
-  void static FindSplitConditions(const std::vector<CPUExpandEntry>& nodes, const RegTree& tree,
+  static void FindSplitConditions(const std::vector<CPUExpandEntry>& nodes, const RegTree& tree,
                                   const GHistIndexMatrix& gmat,
                                   std::vector<int32_t>* split_conditions);
   /**