error in expr. with array or wrong in documentation ?

  Good day.
  
  System Configuration
  ---------------------
    Architecture: Intel Pentium
    Operating System: FreeBSD 4.2-STABLE
    PostgreSQL version:   PostgreSQL-7.1RC1 or 7.1.1
    Compiler used:  gcc 2.95.2
  
  Description of problem
  ----------------------
Chapter 6. Arrays (In Documentation). It say:
   To search the entire array (not just specified columns), you could
   use:                 
SELECT * FROM sal_emp WHERE pay_by_quarter *= 10000;

But, If client try to execute query, for example:
select * from pg_group where grolist *= 1003::integer;

Then it received message: ERROR:  Unable to identify an operator '*=' for types
'_int4' and 'int4'
You will have to retype this query using an explicit cast


    Best regards..
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