diff --git a/presto-parser/src/main/java/io/prestosql/sql/ExpressionFormatter.java b/presto-parser/src/main/java/io/prestosql/sql/ExpressionFormatter.java
index 6e36a5bf9c1b7..f3d3d63dec138 100644
--- a/presto-parser/src/main/java/io/prestosql/sql/ExpressionFormatter.java
+++ b/presto-parser/src/main/java/io/prestosql/sql/ExpressionFormatter.java
@@ -765,7 +765,7 @@ static String formatGroupBy(List<GroupingElement> groupingElements)
             else if (groupingElement instanceof GroupingSets) {
                 result = format("GROUPING SETS (%s)", Joiner.on(", ").join(
                         ((GroupingSets) groupingElement).getSets().stream()
-                                .map(e -> formatGroupingSet(e))
+                                .map(ExpressionFormatter::formatGroupingSet)
                                 .iterator()));
             }
             else if (groupingElement instanceof Cube) {