root@:26257/defaultdb> with recursive x(a) as
  ((values ('a'), ('b'))
   union all
   (with z as (select * from x)
    select z.a || z.a as a from z cross join z as z1
    where length(z.a) < 3))
select * from x;

ERROR: couldn't find WITH expression "x" with ID 1
HINT: references to WITH expressions from correlated subqueries are unsupported