anchor.diff:          (maybe-add-environment-variable (lambda-information-count-arg lambda)))
         (compute-environment-layout (lambda-information-body lambda))
         (setf env-is-dx (finalize-environment-layout lambda)))
  +    (when (gethash lambda *free-variables*)
  +      (push lambda *current-closure-set*))
       (unless env-is-dx
         (setf *allow-dx-environment* nil))))
   
  
positive.code:                                (or (eql (lexical-variable-definition-point var) l)
                                     (lambda-tree-is-dynamic-extent-p l *current-lambda*)))
                               (lexical-variable-used-in var)))
                      (gethash env *environment-layout*)))
      (setf (gethash env *environment-layout-dx*) t)
      t))
  
  
negative.code:     (setf (gethash lambda *lambda-parents*) *current-lambda*)
      (let ((*active-environment-vector* lambda)
            (*allow-dx-environment* t)
            (*current-lambda* lambda)
            (*current-closure-set* '()))
        (assert (null (lambda-information-environment-arg lambda)))
        (check-simple-lambda-parameters lambda)
        (dolist (arg (lambda-information-required-args lambda))
  