Hi,

I’m running the Closer to MOP tests, and see at least one bug. (With the limited time I have available, I can only do one bug at a time, step by step, so there might be more.)

Armed Bear Common Lisp 1.9.0
Java 17.0.3 Azul Systems, Inc.
OpenJDK 64-Bit Server VM
Low-level initialization completed in 0.095 seconds.
Startup completed in 0.469 seconds.
Loading /Users/costanza/.abclrc completed in 3.554 seconds.
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CL-USER(1): (use-package :mop)

(defclass my-effective-slot-definition (standard-effective-slot-definition)
  ())

(defclass my-class (standard-class)
  ())

(defmethod validate-superclass
           ((class my-class)
            (superclass standard-class))
  t)

(defmethod effective-slot-definition-class
           ((class my-class) &rest initargs)
  (declare (ignore initargs))
  (find-class 'my-effective-slot-definition))

(defclass my-object ()
  ((my-slot :allocation :class))
  (:metaclass my-class))
T
CL-USER(2): CL-USER(2): #<STANDARD-CLASS MY-EFFECTIVE-SLOT-DEFINITION {731A05FD}>
CL-USER(3): CL-USER(3): #<STANDARD-CLASS MY-CLASS {42C6245B}>
CL-USER(4): CL-USER(4): #<STANDARD-METHOD VALIDATE-SUPERCLASS (MY-CLASS STANDARD-CLASS) {4959790F}>
CL-USER(5): CL-USER(5): #<STANDARD-METHOD EFFECTIVE-SLOT-DEFINITION-CLASS (MY-CLASS) {2AAA2CBF}>
CL-USER(6): CL-USER(6): #<THREAD "interpreter" {25793D3C}>: Debugger invoked on condition of type UNBOUND-SLOT
  The slot LOCATION is unbound in the object #<MY-EFFECTIVE-SLOT-DEFINITION {32EB5C37}>.
Restarts:
  0: TOP-LEVEL Return to top level.
[1] CL-USER(7): 

Best,
Pascal