How To Fix WL108 - Expression & has object type & and not & (=reference object type)

SAP Error Message - Details

• Message type: E = Error

• Message class: WL - Workflow: run-time messages

• Message number: 108

• Message text: Expression & has object type & and not & (=reference object type)

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message WL108 - Expression & has object type & and not & (=reference object type) ?

  The SAP error message WL108 indicates that there is a type mismatch in your ABAP code, specifically related to object types. This error typically occurs when you are trying to use an expression that has an object type that does not match the expected reference object type.
  Cause:
  The error message WL108 is triggered when:
  
  You are trying to assign or compare an object of one type to another object of a different type.
  The expression you are using has an object type that is not compatible with the expected reference object type.
  
  Solution:
  To resolve this error, you can take the following steps:
  
  
  Check Object Types: Review the types of the objects involved in the expression. Ensure that they are compatible. You can do this by checking the data dictionary or the definitions of the classes/interfaces involved.
  
  
  Type Casting: If you are certain that the objects can be treated as the same type, you may need to perform a type cast. Use the CAST statement to convert one object type to another, ensuring that the conversion is valid.
  DATA: lo_object TYPE REF TO your_class,
        lo_other_object TYPE REF TO another_class.
  
  lo_object = CAST your_class( lo_other_object ).
  
  
  Use Interfaces: If the objects implement a common interface, consider using the interface type for your variable declarations. This can help avoid type mismatches.
  
  
  Debugging: Use the debugger to inspect the values and types of the objects at runtime. This can help you identify where the type mismatch is occurring.
  
  
  Review Method Signatures: If the error occurs in a method call, check the method signature to ensure that the parameters being passed match the expected types.
  
  
  Related Information:
  
  ABAP Type System: Understanding the ABAP type system, including reference types, value types, and how they interact, can help prevent such errors.
  Object-Oriented Programming in ABAP: Familiarize yourself with the principles of object-oriented programming in ABAP, including inheritance and polymorphism, which can affect type compatibility.
  SAP Documentation: Refer to the official SAP documentation for more details on error messages and type handling in ABAP.
  
  By following these steps, you should be able to identify and resolve the cause of the WL108 error in your SAP ABAP code.