Hi guys,
If I create a generic, say foo, for a particular struct and then later 
reference that method on a different type of struct from within the handler 
method I get an error because the call goes to the original structs method and 
not to the method of the other struct. Is there a way to do this?

Here’s a very artificial example:

#lang racket

(require racket/generic)

(define-generics foo
    [do-foo foo])

(struct A (this other) #:transparent
  #:methods gen:foo
  [(define (do-foo foo)
     (printf "other=~a ~a"
             (A-this foo)
             (do-foo (A-other foo))))])
(struct B (lst) #:transparent
  #:methods gen:foo
  [(define (do-foo foo)
     (printf "lst=~a"
             (B-lst foo)))])

(define b (B '(x y z)))
(define a (A 'a b))

(do-foo b) ;=> lst=(x y z)

(do-foo a) ;=> A-this: contract violation
  expected: A?
  given: (B '(x y z))


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