anchor.diff:        (return))
       (let ((c (following-char)))
         (cond
  -       ((and
  -         (syntax-escape-char-p (preceding-char))
  -         (not (syntax-escape-char-p (char-before-2)))))
  +       ((escape-p (preceding-char) (char-before-2)))
          ((not
            (or
             (syntax-escape-char-p c)
  
positive.code:     (do () (nil)
        (unless (next-char 1)
          (return))
        (unless (and (syntax-escape-char-p (preceding-char))
                     (not (syntax-escape-char-p (char-before-2))))
          (when (eql (following-char) goal-char)
            (next-char 1)
            (return t))))))
  
negative.code:     (do () (nil)
          (unless (next-char 1)
            (return))
        (unless (escape-p (preceding-char) (char-before-2))
          (let ((c (following-char)))
            (cond
             ((eql c paren-char)
  