SQL> var B3 varchar2(20);
SQL> var B2 varchar2(30);
SQL> var B1 varchar2(30);
SQL> exec :B3:='ERETRY'

PL/SQL procedure successfully completed.

SQL> exec :B2:='999999999999999999999999'

PL/SQL procedure successfully completed.

SQL> exec :B1 := REPORT_GEN.T_VARCHAR2_TAB('TEST')
BEGIN :B1 := REPORT_GEN.T_VARCHAR2_TAB('TEST'); END;

             *
ERROR at line 1:
ORA-06550: line 1, column 14:
PLS-00382: expression is of wrong type
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored


SQL>

SQL> desc REPORT_GEN.T_VARCHAR2_TAB
 REPORT_GEN.T_VARCHAR2_TAB TABLE OF VARCHAR2(32767 CHAR)

SQL>

SELECT *
FROM PRDTABLE PRD, 
TABLE (:B1 ) PRVD_NAME_ARR 
WHERE PRD.REQUEST_ID = :B2 
AND NOT EXISTS (SELECT 1 FROM REQ WHERE REQUEST_ID = PRD.REQUEST_ID AND ICS_RFLAG = :B3 ) 
AND PRD.PROVIDER = PRVD_NAME_ARR.COLUMN_VALUE;

SQL> help var

 VARIABLE
 --------

 Declares a bind variable that can be referenced in PL/SQL, or
 lists the current display characteristics for a single variable
 or all variables.

VAR[IABLE] [variable [type]]

 where type represents one of the following:

     NUMBER         CHAR          CHAR (n [CHAR|BYTE])
     NCHAR          NCHAR (n)     VARCHAR2 (n [CHAR|BYTE])
     NVARCHAR2 (n)  CLOB          NCLOB
     REFCURSOR      BINARY_FLOAT  BINARY_DOUBLE

SELECT *
FROM PRDTABLE PRD, 
TABLE (REPORT_GEN.T_VARCHAR2_TAB('TEST')) PRVD_NAME_ARR 
WHERE PRD.REQUEST_ID = :B2 
AND NOT EXISTS (SELECT 1 FROM REQ WHERE REQUEST_ID = PRD.REQUEST_ID AND ICS_RFLAG = :B3 ) 
AND PRD.PROVIDER = PRVD_NAME_ARR.COLUMN_VALUE;

SQL> desc REPORT_GEN.T_VARCHAR2_TAB
 REPORT_GEN.T_VARCHAR2_TAB TABLE OF VARCHAR2(32767 CHAR)

SQL> var B1=TABLE
SP2-0552: Bind variable "b1" not declared.
SQL>  var B1=REPORT_GEN.T_VARCHAR2_TAB
SP2-0552: Bind variable "b1" not declared.
SQL> var B1=T_VARCHAR2_TAB
SP2-0552: Bind variable "b1" not declared.
SQL>