Is it possible to add ON DELETE CASCADE to a foreign key that is used as a partitioning key when used with PARTITION BY REFERENCE?

My solution would be to drop the constraint and recreate it, but it doesn't work, as I cannot drop a constraint that is used by PARTITION BY REFERENCE.

I get SQL Error: ORA-14650: operation not supported for reference-partitioned tables

Oracle 11g.

drop table y;
drop table x;
create table x (a number primary key) partition by hash (a);
create table y (a number not null,
   constraint y_x_fk foreign key(a) references x(a))
   partition by reference(y_x_fk);
alter table y drop constraint y_x_fk;

create table x (a number primary key) partition by hash (a);

create table y (a number not null,
  constraint y_x_fk foreign key(a) references x(a) on delete cascade
) partition by reference(y_x_fk);

insert into x values (1);
insert into y values (1);
select count(*) from y;

COUNT(*)  
1 

delete x where a = 1;

select count(*) from y;

COUNT(*)  
0