How To Fix WER166 - DDIC type &1 is not supported as a return parameter

SAP Error Message - Details

• Message type: E = Error

• Message class: WER - Messages for the package WER

• Message number: 166

• Message text: DDIC type &1 is not supported as a return parameter

Self-Explanatory Message

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• What is the cause and solution for SAP error message WER166 - DDIC type &1 is not supported as a return parameter ?

  SAP Error Message:
  
  WER166 - DDIC type &1 is not supported as a return parameter
  
  Cause
  This error occurs when a function module or method is defined with a return parameter whose data type is a Data Dictionary (DDIC) type that is not supported as a return parameter. In SAP ABAP, certain DDIC types cannot be used directly as return parameters in function modules or methods. For example, complex types like table types, deep structures, or certain reference types are not allowed as return parameters.
  The system checks the return parameter's type during the activation or runtime of the function module/method and raises this error if the type is unsupported.
  
  Explanation
  
  Return parameters in function modules or methods must be of a type that can be passed back as a single value.
  Unsupported DDIC types include:
  
  Table types (internal tables)
  Deep structures
  Certain reference types
  Possibly some complex or nested types
  
  
  Supported types are usually elementary types or flat structures.
  
  
  Solution
  
  
  Change the return parameter type:
  
  Instead of using an unsupported DDIC type as a return parameter, use a supported type.
  For example, if you need to return a table, use an exporting parameter or a changing parameter instead of a return parameter.
  If you need to return complex data, consider returning a structure or a simple type, or use exporting parameters.
  
  
  
  Use exporting/changing parameters for complex data:
  
  For tables or complex structures, define them as exporting or changing parameters rather than return parameters.
  
  
  
  Redesign the function module or method interface:
  
  Adjust the interface to comply with SAP's restrictions on return parameters.
  
  
  
  
  Related Information
  
  SAP documentation on Function Module Interfaces and Method Interfaces.
  SAP Note or SAP Help Portal entries related to function module parameter types.
  ABAP programming guidelines on parameter passing.
  In ABAP Objects, methods can have only one return parameter, and it must be a simple or flat type.
  
  
  Example
  Incorrect:
  FUNCTION z_my_function.
    " Return parameter of type table type (unsupported)
    RETURNING VALUE(rt_data) TYPE ztt_my_table_type.
  ENDFUNCTION.
  Correct:
  FUNCTION z_my_function.
    " Use exporting parameter for table type
    EXPORTING et_data TYPE ztt_my_table_type.
  ENDFUNCTION.
  
  Summary
  
  
  
  Aspect
  Details
  
  
  
  
  Error
  WER166 DDIC type &1 is not supported as a return parameter
  
  
  Cause
  Unsupported DDIC type used as return parameter (e.g., table types)
  
  
  Solution
  Use supported types for return parameters; use exporting/changing parameters for complex types
  
  
  Related Info
  SAP documentation on function module/method interfaces
  
  
  
  
  If you provide the exact function module or method signature, I can help you refactor it to avoid this error.