[CALCITE-5439] Validation of Pivot fails after creating a deep copy o…

…f SqlNode

core/src/main/java/org/apache/calcite/sql/SqlPivot.java

@@ -35,6 +35,8 @@
 import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * Parse tree node that represents a PIVOT applied to a table reference
  * (or sub-query).
@@ -195,5 +197,16 @@ static class Operator extends SqlSpecialOperator {
     Operator(SqlKind kind) {
       super(kind.name(), kind);
     }
+
+    @Override public SqlCall createCall(
+        @Nullable SqlLiteral functionQualifier,
+        SqlParserPos pos,
+        @Nullable SqlNode... operands) {
+      assert operands.length == 4;
+      return new SqlPivot(pos, requireNonNull(operands[0], "query"),
+          requireNonNull((SqlNodeList) operands[1], "aggList"),
+          requireNonNull((SqlNodeList) operands[2], "axisList"),
+          requireNonNull((SqlNodeList) operands[3], "inList"));
+    }
   }
 }

testkit/src/main/java/org/apache/calcite/sql/parser/SqlParserTest.java

@@ -9044,6 +9044,28 @@ private static Consumer<List<? extends Throwable>> checkWarnings(
     sql(sql).ok(expected);
   }
 
+  @Test void testPivotThroughShuttle() {
+    final String sql = ""
+        + "SELECT *\n"
+        + "FROM (SELECT job, deptno FROM \"EMP\")\n"
+        + "PIVOT (COUNT(*) AS \"COUNT\" FOR deptno IN (10, 50, 20))";
+    final String expected = ""
+        + "SELECT *\n"
+        + "FROM (SELECT `JOB`, `DEPTNO`\n"
+        + "FROM `EMP`) PIVOT (COUNT(*) AS `COUNT` FOR `DEPTNO` IN (10, 50, 20))";
+    final SqlNode sqlNode = sql(sql).node();
+
+    final SqlNode shuttled = sqlNode.accept(new SqlShuttle() {
+      @Override public @Nullable SqlNode visit(final SqlCall call) {
+        // Handler always creates a new copy of 'call'
+        CallCopyingArgHandler argHandler = new CallCopyingArgHandler(call, true);
+        call.getOperator().acceptCall(this, call, false, argHandler);
+        return argHandler.result();
+      }
+    });
+    assertThat(toLinux(shuttled.toString()), is(expected));
+  }
+
   @Test void testMatchRecognize1() {
     final String sql = "select *\n"
         + "  from t match_recognize\n"