Oracle collection error for assign variable of table to another

DECLARE
  TYPE table_type_1 IS TABLE OF NUMBER(10);
  TYPE table_type_2 IS TABLE OF NUMBER(10);
  v_tab_1  table_type_1;
  v_tab_2  table_type_2;
BEGIN
  -- Initialise the collection with two values.
  v_tab_1 := table_type_1(1, 2);

  -- Assignment causes compilation error.
  v_tab_2 := v_tab_1;
END;
/

  v_tab_2 := v_tab_1;
             *
ERROR at line 11:
ORA-06550: line 11, column 14:
PLS-00382: expression is of wrong type
ORA-06550: line 11, column 3:
PL/SQL: Statement ignored


SQL>