anchor.diff:                ,@macro-body)
               ,expr ,clauses
               :default-keys ',default-keys
  -            :error ',error))))))
  +            :error ',error
  +            :macro-name ',name))))))
   
   (defun clauses+default (clauses &key (default-keys '(t otherwise)))
     (let ((default-clause-tails
  
positive.code:             (assert (listp default))
              (assert (listp clauses))
              (funcall cont expr-temp default clauses)))
          (expr-temp (gensym)))
      ;; Rebind expr.
      `(let ((,expr-temp ,expr))
         ,(multiple-value-bind (clauses default)
  
negative.code:         else
            collect clause))
  
  (defun expand-case-macro (cont expr clauses
                            &key (default-keys '(t otherwise)) error
                                 (macro-name 'custom-case))
    (check-type clauses list)
    (when (eql error t)
      (setf error 'case-failure))
  