Armed Bear Common Lisp 1.9.0

Java 17.0.3 Azul Systems, Inc.

OpenJDK 64-Bit Server VM

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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): 