2 files changed, 28 insertions, 0 deletions
diff --git a/mysql-test/r/partition_pruning.result b/mysql-test/r/partition_pruning.result
index 16dc23cdf42..d520f7735ec 100644
--- a/mysql-test/r/partition_pruning.result
+++ b/mysql-test/r/partition_pruning.result
@@ -583,3 +583,17 @@ explain partitions select * from t1 where a>='a' and a <= 'dddd';
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	p1,p2,p3,p4,p5	ALL	NULL	NULL	NULL	NULL	5	Using where
 drop table t1;
+create table t1 (f_int1 integer) partition by list(abs(mod(f_int1,2)))
+subpartition by hash(f_int1) subpartitions 2
+(
+partition part1 values in (0),
+partition part2 values in (1),
+partition part4 values in (null)
+);
+insert into t1 set f_int1 = null;
+select * from t1 where f_int1 is null;
+f_int1
+NULL
+explain partitions select * from t1 where f_int1 is null;
+id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	part4_p2sp0	system	NULL	NULL	NULL	NULL	1	
diff --git a/mysql-test/t/partition_pruning.test b/mysql-test/t/partition_pruning.test
index 25320e9f80d..63d389f2c06 100644
--- a/mysql-test/t/partition_pruning.test
+++ b/mysql-test/t/partition_pruning.test
@@ -479,5 +479,19 @@ select * from t1 where a>='a' and a <= 'dddd';
 explain partitions select * from t1 where a>='a' and a <= 'dddd';
 drop table t1;
 
+# BUG#18659: Assertion failure when subpartitioning is used and partition is
+# "IS NULL"
+create table t1 (f_int1 integer) partition by list(abs(mod(f_int1,2)))
+  subpartition by hash(f_int1) subpartitions 2
+(
+  partition part1 values in (0),
+  partition part2 values in (1),
+  partition part4 values in (null)
+);
+insert into t1 set f_int1 = null;
+
+select * from t1 where f_int1 is null;
+explain partitions select * from t1 where f_int1 is null;
+
 # No tests for NULLs in RANGE(monotonic_expr()) - they depend on BUG#15447
 # being fixed.