Select query with nested table using synonym does not work, getting error "ORA-04043" (4253505)

Select query with nested table using synonym does not work. The following code does not work in Toad for Oracle 10, but works in SQL Plus.

-- drop type a_T
CREATE OR REPLACE TYPE A__T AS OBJECT
(
NAME VARCHAR2(30),
area NUMBER
) ;

CREATE PUBLIC SYNONYM a_t FOR a__T;

CREATE OR REPLACE TYPE a_nt
AS TABLE OF a_t;


SELECT a_nt(a_t(LB,1),a_t(KG,100)) FROM dual


This does not work in Toad, will get error "ORA-04043: object "SALES"."A_T" does not exist", but it works in fine in SQL Plus.