gentst.scm

(define-module (gentst)
  #:use-module  (oop goops)
  #:use-module  (gentst1)
  #:use-module  (gentst2)

  #:export      (test)
  #:re-export   (foo)
  
  #:duplicates  (merge-generics))

(define (test)
  (foo (make <gentst1>))
  (foo (make <gentst2>)))

gentst1.scm

(define-module (gentst1)
  #:use-module (oop goops)
  #:export (<gentst1> foo))

(define-class <gentst1> (<object>))

(define-method (foo (self <gentst1>))
  (display "gentst1 foo called\n"))

gentst2.scm

(define-module (gentst2)
  #:use-module (oop goops)
  #:export (<gentst2> foo))

(define-class <gentst2> (<object>))

(define-method (foo (self <gentst2>))
  (display "gentst2 foo called\n"))

gistfile1.txt

# force recompilation
akren:~ % touch gentst.scm gentst1.scm gentst2.scm

akren:~ % guile3
GNU Guile 3.0.7
scheme@(guile-user)> (add-to-load-path ".")
scheme@(guile-user)> ,use (gentst)
;;; note: source file ./gentst.scm
;;;       newer than compiled /home/andrew/.cache/guile/ccache/3.0-LE-8-4.5/home/andrew/gentst.scm.go
;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
;;;       or pass the --no-auto-compile argument to disable.
;;; compiling ./gentst.scm
;;; note: source file ./gentst1.scm
;;;       newer than compiled /home/andrew/.cache/guile/ccache/3.0-LE-8-4.5/home/andrew/gentst1.scm.go
;;; compiling ./gentst1.scm
;;; compiled /home/andrew/.cache/guile/ccache/3.0-LE-8-4.5/home/andrew/gentst1.scm.go
;;; note: source file ./gentst2.scm
;;;       newer than compiled /home/andrew/.cache/guile/ccache/3.0-LE-8-4.5/home/andrew/gentst2.scm.go
;;; compiling ./gentst2.scm
;;; compiled /home/andrew/.cache/guile/ccache/3.0-LE-8-4.5/home/andrew/gentst2.scm.go
WARNING: (gentst): `foo' imported from both (gentst1) and (gentst2)
;;; compiled /home/andrew/.cache/guile/ccache/3.0-LE-8-4.5/home/andrew/gentst.scm.go
scheme@(guile-user)> (test)
gentst1 foo called
gentst2 foo called
scheme@(guile-user)> foo
$1 = #<<extended-generic> foo (2)>
scheme@(guile-user)> 

# try again without recompilation 
akren:~ % guile3                                  
GNU Guile 3.0.7
scheme@(guile-user)> (add-to-load-path ".")
scheme@(guile-user)> ,use (gentst)
WARNING: (gentst): `foo' imported from both (gentst1) and (gentst2)
scheme@(guile-user)> (test)
ice-9/boot-9.scm:1685:16: In procedure raise-exception:
No applicable method for #<<generic> foo (1)> in call (foo #<<gentst1> 805737fb0>)

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> 

scheme@(guile-user)> foo
$1 = #<<generic> foo (1)>
scheme@(guile-user)>