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ARTICLE

Cannot Use Field Symbols As Class Components
You cannot declare field symbols as components of classes in the declaration part of the class definition. However, you can create local field symbols within methods.

In the declaration part of the class, the following statement causes an error message::

FIELD-SYMBOLS ...

Correct syntax:

DATA ... TYPE REF TO ...
or
ALIASES ...

Cause:

The only components allowed in classes are attributes, methods, and events. Field symbols are symbolic names for other fields. They work by means of value semantics. Their role as pointers is now performed in ABAP Objects by reference variables. Their role as symbolic names has now been replaced by aliases.