2 files changed, 27 insertions, 0 deletions
diff --git a/src/test/regress/expected/with.out b/src/test/regress/expected/with.out
index 2c3e36f5fe1..1226fbc9f4a 100644
--- a/src/test/regress/expected/with.out
+++ b/src/test/regress/expected/with.out
@@ -627,6 +627,21 @@ SELECT t1.id, t2.path, t2 FROM t AS t1 JOIN t AS t2 ON
  16 | {3,7,11,16} | (16,"{3,7,11,16}")
 (16 rows)
 
+CREATE TEMP TABLE duplicates (a INT NOT NULL);
+INSERT INTO duplicates VALUES(1), (1);
+-- Try out a recursive UNION case where the non-recursive part's table slot
+-- uses TTSOpsBufferHeapTuple and contains duplicate rows.
+WITH RECURSIVE cte (a) as (
+	SELECT a FROM duplicates
+	UNION
+	SELECT a FROM cte
+)
+SELECT a FROM cte;
+ a 
+---
+ 1
+(1 row)
+
 --
 -- test cycle detection
 --
diff --git a/src/test/regress/sql/with.sql b/src/test/regress/sql/with.sql
index c2d1555fb08..bae20e0d841 100644
--- a/src/test/regress/sql/with.sql
+++ b/src/test/regress/sql/with.sql
@@ -339,6 +339,18 @@ UNION ALL
 SELECT t1.id, t2.path, t2 FROM t AS t1 JOIN t AS t2 ON
 (t1.id=t2.id);
 
+CREATE TEMP TABLE duplicates (a INT NOT NULL);
+INSERT INTO duplicates VALUES(1), (1);
+
+-- Try out a recursive UNION case where the non-recursive part's table slot
+-- uses TTSOpsBufferHeapTuple and contains duplicate rows.
+WITH RECURSIVE cte (a) as (
+	SELECT a FROM duplicates
+	UNION
+	SELECT a FROM cte
+)
+SELECT a FROM cte;
+
 --
 -- test cycle detection
 --