COBCH2325 Variable length group cannot be a parameter to a section

A section cannot have a variable length group as a parameter.

See example below.

       01  string-t typedef.
          03  len     pic x(4) comp-5.
          03  str.
             05  char      pic x occurs 1 to 40 depending on len. *> Remove this line

       01  s1  string-t.

         perform display-str(reference s1)
         goback
         .
       display-str section(reference p0 as string-t).
         display "<" str of p0 ">"