MDEV-23823 Crash in SELECT NEXT VALUE on locked view

Make open_table() fail if sequence should be opened, but it turns out to
be locked view.

mysql-test/suite/sql_sequence/next.result

@@ -534,3 +534,12 @@ select next value for s;
 next value for s
 -999
 drop sequence s;
+#
+# MDEV-23823 NEXT VALUE crash on locked view
+#
+CREATE VIEW v AS SELECT 1;
+LOCK TABLE v READ;
+SELECT NEXT VALUE FOR v;
+ERROR 42S02: 'test.v' is not a SEQUENCE
+UNLOCK TABLES;
+DROP VIEW v;

mysql-test/suite/sql_sequence/next.test

@@ -280,3 +280,13 @@ select next value for s;
 flush tables;
 select next value for s;
 drop sequence s;
+
+--echo #
+--echo # MDEV-23823 NEXT VALUE crash on locked view
+--echo #
+CREATE VIEW v AS SELECT 1;
+LOCK TABLE v READ;
+--error ER_NOT_SEQUENCE
+SELECT NEXT VALUE FOR v;
+UNLOCK TABLES;
+DROP VIEW v;

sql/sql_base.cc

@@ -1724,7 +1724,14 @@ bool open_table(THD *thd, TABLE_LIST *table_list, Open_table_context *ot_ctx)
     }
 
     if (is_locked_view(thd, table_list))
+    {
+      if (table_list->sequence)
+      {
+        my_error(ER_NOT_SEQUENCE, MYF(0), table_list->db.str, table_list->alias.str);
+        DBUG_RETURN(true);
+      }
       DBUG_RETURN(FALSE); // VIEW
+    }
 
     /*
       No table in the locked tables list. In case of explicit LOCK TABLES