How To Fix W8137 - Constants cannot be declared here

SAP Error Message - Details

• Message type: E = Error

• Message class: W8 - Workflow: Expressions, data flow

• Message number: 137

• Message text: Constants cannot be declared here

What causes this issue?

You tried to specify a constant for an expression. This is not possible
in this situation since the destination of the binding must be a
variable, that is a container element.

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?

Either enter a variable expression in the form &Elementname& or define
an expression using the input help.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message W8137 - Constants cannot be declared here ?

  SAP Error Message:
  
  W8137 - Constants cannot be declared here
  
  Cause:
  This warning occurs when you try to declare a constant in a part of the ABAP program where constant declarations are not allowed. In ABAP, constants must be declared in specific sections such as the TOP INCLUDE, DATA DECLARATION part of a program, or within a CLASS or INTERFACE definition, but not inside executable code blocks like FORM routines, METHODS, or inside procedural code blocks.
  For example, declaring a constant inside a FORM or METHOD implementation or inside a procedural block will trigger this warning.
  
  Explanation:
  
  Constants are static values that do not change during program execution.
  They must be declared in the global or local declaration part of the program or class.
  Declaring constants inside procedural code is syntactically incorrect.
  
  
  Solution:
  
  Move the constant declaration to an appropriate place:
  
  For report programs or function modules, declare constants in the TOP INCLUDE or the global declaration section.
  For class-based programs, declare constants in the CLASS or INTERFACE definition part (e.g., in the CLASS ... DEFINITION section).
  
  
  If you need a constant value inside a method or form, declare it as a constant in the class or program global section and then use it inside the method or form.
  
  
  Example:
  Incorrect:
  FORM my_form.
    CONSTANTS c_value TYPE i VALUE 10. " This causes W8137
  ENDFORM.
  Correct:
  CONSTANTS c_value TYPE i VALUE 10.
  
  FORM my_form.
    " Use c_value here
  ENDFORM.
  Or inside a class:
  CLASS lcl_example DEFINITION.
    PUBLIC SECTION.
      CONSTANTS c_value TYPE i VALUE 10.
      METHODS display.
  ENDCLASS.
  
  CLASS lcl_example IMPLEMENTATION.
    METHOD display.
      WRITE: / c_value.
    ENDMETHOD.
  ENDCLASS.
  
  Related Information:
  
  SAP Documentation: Check ABAP keyword documentation for CONSTANTS.
  ABAP Programming Guidelines: Constants should be declared in global or class definition parts.
  Other similar messages: W8136 (Data declarations not allowed here), which also relates to incorrect declaration placement.
  
  
  Summary:
  
  Cause: Declaring constants in procedural code blocks.
  Solution: Declare constants in global or class definition sections.
  Best Practice: Keep constants at the top or in class definitions for clarity and maintainability.
  
  
  If you need further help, please provide the code snippet causing the warning!