PLS-00363: expression 'I' cannot be used as an assignment target

Question

Hello all
I have a Package and I have one procedure in it .
I have use dmlset inside this .
Inside that procedure I have a cursor and inside the FOR loop I have mentioned something .
FOR i IN 1 .. No_of_rec LOOP
If....
End if ;
i := i+1 ;
END LOOP;
I have mentioned before end loop i := i+1 ; when i execute this package it is showing this error .
"PLS-00363: expression 'I' cannot be used as an assignment target"
What could be the problem?

Answer 1

Of course,
My example is showing that index I in loop is same thing as parameter IN in procedure1. Its value, not reference. I is passed as VALUE to LOOP just like PARAM1 is passed as value to PROCEDURE1. Trying to assignment something to I or PARAM1 will generate same error.
Also another interesting example is
CREATE OR REPLACE
PROCEDURE procedure1(
    param1 IN OUT NUMBER)
AS
BEGIN
  param1 := 0;
END procedure1;
BEGIN
  FOR i IN 1..3
  LOOP
    procedure1(i);
  END LOOP;
END;
In this case procedure1 is correct but loop stmt is not. It will generate same error.
After doing this examples i also concluded that procedure cant return value it can modify existing value of variable which is declared (uninitialized or initialized, OUT or IN OUT ) in upper PLSQL block (named or unnamed PLSQL block)