ABAP Objects error message at:
ON CHANGE OF f.
...
ENDON.
Correct syntax:
DATA g LIKE f.
IF
f <> g.
...
g = f.
ENDIF.
Reason:
The system internally creates a global invisible work field which cannot be controlled
by the program. You are recommended to declare your own work field and process it with the IF control structure.
Overview:
Replacement for Obsolete Statements ABAP Objects