anchor.diff:  (in-package :nyxt/migration)
   
   (defparameter +migration-suggestions+ (sera:dict)
  -  "Map between symbols and `suggestion's.")
  +  "Map between symbol names and `suggestion's.
  +
  +We use symbol names because when an error occurs because of an unbound symbol,
  +we cannot predict the package in which it happened.")
   
   (define-class suggestion ()
     ((symbols
  
positive.code: 
  (export-always 'find-suggestions)
  (defun find-suggestions (string)
    (gethash (alex:symbolicate (string-upcase string)) +migration-suggestions+))
  
  (defmacro define-migration (major-version-string &body body)
    (let ((result '()))
  
negative.code: 
  (defmethod initialize-instance :after ((suggestion suggestion) &key)
    (dolist (sym (symbols suggestion))
      (when (gethash (symbol-name sym) +migration-suggestions+)
        (alex:deletef (gethash (symbol-name sym) +migration-suggestions+)
                      suggestion
                      :test #'suggestion=))
      (push suggestion (gethash (symbol-name sym) +migration-suggestions+))))
  
  (defun version-suggestions (major-version)
    (let ((result '()))
  