MDEV-18800 Server crash in instant_alter_column_possible or Assertion...

 `!pk->has_virtual()' failed in instant_alter_column_possible upon adding key

Hash key can't be primary key.

mysql-test/main/long_unique_bugs.result

@@ -112,3 +112,20 @@ ERROR 42000: Can't DROP COLUMN `x`; check that it exists
 SELECT * FROM t1 WHERE f LIKE 'foo';
 f
 DROP TABLE t1;
+CREATE TABLE t1 (pk INT, PRIMARY KEY USING HASH (pk)) ENGINE=InnoDB;
+show keys from t1;;
+Table	t1
+Non_unique	0
+Key_name	PRIMARY
+Seq_in_index	1
+Column_name	pk
+Collation	A
+Cardinality	0
+Sub_part	NULL
+Packed	NULL
+Null	
+Index_type	BTREE
+Comment	
+Index_comment	
+ALTER TABLE t1 ADD INDEX (pk);
+DROP TABLE t1;

mysql-test/main/long_unique_bugs.test

@@ -141,3 +141,12 @@ CREATE TABLE t1 (f VARCHAR(4096), UNIQUE(f)) ENGINE=InnoDB;
 ALTER TABLE t1 DROP x;
 SELECT * FROM t1 WHERE f LIKE 'foo';
 DROP TABLE t1;
+
+#
+# MDEV-18800 Server crash in instant_alter_column_possible or
+#   Assertion `!pk->has_virtual()' failed in instant_alter_column_possible upon adding key
+#
+CREATE TABLE t1 (pk INT, PRIMARY KEY USING HASH (pk)) ENGINE=InnoDB;
+--query_vertical show keys from t1;
+ALTER TABLE t1 ADD INDEX (pk);
+DROP TABLE t1;

sql/sql_table.cc

@@ -4179,6 +4179,7 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
     }
     if (is_hash_field_needed ||
         (key_info->algorithm == HA_KEY_ALG_HASH &&
+         key->type != Key::PRIMARY &&
          key_info->flags & HA_NOSAME &&
          !(file->ha_table_flags() & HA_CAN_HASH_KEYS ) &&
          file->ha_table_flags() & HA_CAN_VIRTUAL_COLUMNS))