anchor.diff:          ;; Default initform when type is missing:
           nil)))
   
  -(defun nil-fallback-type-zero-function (definition)
  +(defun nil-fallback-initform-inference (definition)
     "Infer basic type zero values.
   Fall back to nil if initform is missing for unsupported types."
     (let ((type (definition-type definition)))
  
positive.code:         ;; Default initform when type is missing:
          nil)))
  
  (defun no-unbound-type-zero-function (definition)
    "Infer basic type zero values.
  Raise a condition when instantiating if initform is missing for unsupported types."
    (let ((type (definition-type definition)))
  
negative.code:                   ,(mapcar #'process-slot-initform slots)
                    ,@options)
                  (setf (find-class ',name) (find-class ',temp-name))))
        (let* ((option-type (assoc :initform-inference options))
               (initform-inference (or (when option-type
                                         (setf options (delete :initform-inference options :key #'car))
                                         (eval (second option-type)))
                                       *initform-inference*)))
          `(hu.dwim.defclass-star:defclass* ,name ,supers
             ,(mapcar (lambda (definition)
                        (process-slot-initform definition initform-inference))
                      slots)
             ,@options))))
  