title: short Dump: Field symbol has not yet been assigned
body: <p>I am getting a short dump (Field symbol has not yet been assigned) when I run this program.
  I know that I may get this error when I don't fill the <code>t_fieldcat</code> correctly.
  As far as I know I have filled the field catalog correctly.</p>
  
  <p>I cannot figure out where the problem is..Please help.</p>
  
  <pre><code>REPORT  Y_ALV1.
  
  type-pools slis.
  tables: scarr.
  
  data:
        t_scarr type table of scarr,
        t_fieldcat type slis_t_fieldcat_alv.
  
  data:
        wa_fieldcat type slis_fieldcat_alv.
  
  select-options:
        s_carrid for scarr-carrid.
  
  start-of-selection.
        select * into table t_scarr from scarr where carrid in s_carrid.
          if sy-subrc ne 0.
            leave list-processing.
            endif.
  
  define fill_fieldcatalog.
    wa_fieldcat-col_pos = &amp;1.
    wa_fieldcat-fieldname = &amp;2.
    wa_fieldcat-tabname = &amp;3.
    wa_fieldcat-outputlen = &amp;4.
  
    append wa_fieldcat to t_fieldcat.
  
    end-of-definition.
  
  
    fill_fieldcatalog 1 'carrid' 't_scarr' 10.
    fill_fieldcatalog 2 'carrname' 't_scarr' 10.
  
    CALL FUNCTION 'REUSE_ALV_LIST_DISPLAY'
     EXPORTING
        IT_FIELDCAT                    = t_fieldcat
      TABLES
        T_OUTTAB                       = t_scarr
     EXCEPTIONS
       PROGRAM_ERROR                  = 1
       OTHERS                         = 2
              .
    IF SY-SUBRC &lt;&gt; 0.
   MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
           WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
    ENDIF.
  </code></pre>