Parameter &1 will become hidden variable for current date, lang. or user

What causes this issue?

Parameter &V1& uses special data type &V2& and has no annotations
specifying a derivation or default value. For compatibility reasons
<(>,<)> it will therefore be converted into a hidden BW Variable filled
with the current date, logon language and user (depending on the data
type).

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

To avoid this implicit conversion, avoid data types SYLANGU, SYDATE and
SYUSER, provide a derivation or default value<(>,<)> or explicitely set
@Consumption.hidden to False.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.