diff --git a/core/src/main/java/org/apache/calcite/tools/RelBuilder.java b/core/src/main/java/org/apache/calcite/tools/RelBuilder.java
index 148f43028604..11857d3fcbac 100644
--- a/core/src/main/java/org/apache/calcite/tools/RelBuilder.java
+++ b/core/src/main/java/org/apache/calcite/tools/RelBuilder.java
@@ -2503,9 +2503,9 @@ private RelBuilder pruneAggregateInputFieldsAndDeduplicateAggCalls(
           builder.add(project.getRowType().getFieldList().get(i));
         }
 
-        r =
-            project.copy(project.getTraitSet().apply(targetMapping), project.getInput(),
-                newProjects, builder.build());
+        r = project.copy(project.getTraitSet().apply(targetMapping), project.getInput(), newProjects, builder.build());
+        r = project.copy(project.getTraitSet(), project.getInput(), newProjects, builder.build());
+        //r = project.copy(cluster.traitSet(), project.getInput(), newProjects, builder.build());
       } else {
         groupSetAfterPruning = groupSet;
         groupSetsAfterPruning = groupSets;
diff --git a/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java b/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java
index 24b06aedee62..f6cddadd5555 100644
--- a/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java
+++ b/core/src/test/java/org/apache/calcite/test/RelBuilderTest.java
@@ -22,10 +22,13 @@
 import org.apache.calcite.plan.Contexts;
 import org.apache.calcite.plan.Convention;
 import org.apache.calcite.plan.RelOptTable;
+import org.apache.calcite.plan.RelOptUtil;
 import org.apache.calcite.plan.RelTraitDef;
 import org.apache.calcite.plan.RelTraitSet;
+import org.apache.calcite.rel.RelCollation;
 import org.apache.calcite.rel.RelCollations;
 import org.apache.calcite.rel.RelDistributions;
+import org.apache.calcite.rel.RelFieldCollation;
 import org.apache.calcite.rel.RelNode;
 import org.apache.calcite.rel.core.AggregateCall;
 import org.apache.calcite.rel.core.Correlate;
@@ -548,27 +551,105 @@ private void checkSimplify(UnaryOperator<RelBuilder.Config> transform,
   }
 
   /** Test case for
-   * <a href="https://issues.apache.org/jira/projects/CALCITE/issues/CALCITE-6340">
-   * [CALCITE-6340] RelBuilder always creates Project with Convention.NONE during aggregate_.</a>.
+   * <a href="https://issues.apache.org/jira/browse/CALCITE/issues/CALCITE-6340">[CALCITE-6340]
+   * RelBuilder always creates Project with Convention.NONE during aggregate_.</a>.
+   */
+  @Test void testPruneProjectInputOfAggregatePreservesConventionAndCollations() {
+    final RelBuilder builder = createBuilder(config -> config.withPruneInputOfAggregate(true));
+
+    RelNode node = builder
+        .scan("EMP")
+        .sort(builder.nullsLast(builder.desc(builder.field(0))),
+            builder.field(1))
+        .project(builder.alias(builder.field(0), "a"),
+            builder.alias(builder.field(1), "b"),
+            builder.alias(builder.field(0), "c"),
+            builder.alias(builder.field(1), "d"))
+        .build();
+    System.out.println("TRAITS: " + node.getTraitSet());
+    System.out.println(RelOptUtil.toString(node));
+
+    RelTraitSet desiredTraits = builder.getCluster().traitSet()
+        .replace(EnumerableConvention.INSTANCE);
+
+    RuleSet prepareRules =
+        RuleSets.ofList(EnumerableRules.ENUMERABLE_PROJECT_RULE,
+            EnumerableRules.ENUMERABLE_SORT_RULE,
+            EnumerableRules.ENUMERABLE_TABLE_SCAN_RULE);
+    Program program = Programs.of(prepareRules);
+    node = program.run(node.getCluster().getPlanner(), node,
+            desiredTraits, ImmutableList.of(), ImmutableList.of());
+    System.out.println("TRAITS: " + node.getTraitSet());
+    System.out.println(RelOptUtil.toString(node));
+
+    node = builder.push(node)
+        .aggregate(builder.groupKey(0), builder.aggregateCall(
+            SqlStdOperatorTable.SUM, builder.field(0)))
+        .build();
+
+    RelTraitSet relTraitSet = node.getInput(0).getTraitSet();
+    System.out.println(relTraitSet);
+    System.out.println(RelOptUtil.toString(node));
+
+    final RelCollation collation1 = RelCollations.of(new RelFieldCollation(1,
+                RelFieldCollation.Direction.DESCENDING, RelFieldCollation.NullDirection.LAST),
+            new RelFieldCollation(0));
+
+    assertTrue(relTraitSet.contains(EnumerableConvention.INSTANCE));
+    assertTrue(relTraitSet.getTrait(1).satisfies(collation1));
+  }
+
+  /** Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE/issues/CALCITE-6340">[CALCITE-6340]
+   * RelBuilder always creates Project with Convention.NONE during aggregate_.</a>.
+   */
+  @Test void testPruneProjectInputOfAggregatePreservesConventionAndDistribution() {
+    final RelBuilder builder = createBuilder(config -> config.withPruneInputOfAggregate(true));
+
+    RelNode node = builder
+        .scan("EMP")
+        .project(builder.alias(builder.field(0), "a"),
+            builder.alias(builder.field(0), "b"),
+            builder.alias(builder.field(1), "c"))
+        .build();
+    RelTraitSet desiredTraits = builder.getCluster().traitSet()
+        .replace(EnumerableConvention.INSTANCE);
+
+    RuleSet prepareRules =
+        RuleSets.ofList(EnumerableRules.ENUMERABLE_PROJECT_RULE,
+            EnumerableRules.ENUMERABLE_TABLE_SCAN_RULE);
+    Program program = Programs.of(prepareRules);
+    node = program.run(node.getCluster().getPlanner(), node,
+        desiredTraits, ImmutableList.of(), ImmutableList.of());
+
+    node = node.copy(desiredTraits.plus(RelDistributions.BROADCAST_DISTRIBUTED), node.getInputs());
+
+    node = builder.push(node)
+        .aggregate(builder.groupKey(0), builder.aggregateCall(
+            SqlStdOperatorTable.SUM, builder.field(0)))
+        .build();
+
+    RelTraitSet relTraitSet = node.getInput(0).getTraitSet();
+    assertTrue(relTraitSet.contains(EnumerableConvention.INSTANCE));
+    assertTrue(relTraitSet.contains(RelDistributions.BROADCAST_DISTRIBUTED));
+  }
+
+  /** Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE/issues/CALCITE-6340">
+   * [CALCITE-6340] RelBuilder drops set conventions when aggregating over duplicate
+   * projected fields.</a>.
    */
   @Test void testPruneProjectInputOfAggregatePreservesTraitSet() {
     final RelBuilder builder = createBuilder(config -> config.withPruneInputOfAggregate(true));
 
-    // This issue only occurs when projecting more columns than there are fields and putting
-    // an aggregate over that projection.
-    RelNode root =
-        builder.scan("DEPT")
-            .adoptConvention(EnumerableConvention.INSTANCE)
-            .project(builder.alias(builder.field(0), "a"),
-                builder.alias(builder.field(1), "b"),
-                builder.alias(builder.field(2), "c"),
-                builder.alias(builder.field(1), "d"))
-            .aggregate(builder.groupKey(0, 1, 2, 1),
-                builder.aggregateCall(SqlStdOperatorTable.SUM,
-                    builder.field(0)))
-            .build();
+    final RelNode root = builder.scan("DEPT")
+        .adoptConvention(EnumerableConvention.INSTANCE)
+        .project(builder.alias(builder.field(0), "a"),
+            builder.alias(builder.field(0), "b"))
+        .aggregate(
+            builder.groupKey(0), builder.aggregateCall(
+                SqlStdOperatorTable.SUM, builder.field(0))).build();
 
-    // Verify that the project under the aggregate kept the EnumerableConvention.INSTANCE trait.
     assertTrue(root.getInput(0).getTraitSet().contains(EnumerableConvention.INSTANCE));
   }