In gray-stream-mixin.lisp, there are inconsistencies in the lambda lists of generic functions and the corresponding methods:
(defgeneric stream-read-sequence (stream sequence start end &key &allow-other-keys))
(defgeneric stream-write-sequence (stream sequence start end &key &allow-other-keys))
#+clisp (progn (defmethod gray:stream-read-sequence ((s trivial-gray-stream-mixin) seq &optional start end) (stream-read-sequence s seq (or start 0) (or end (length seq))))
(defmethod gray:stream-write-sequence ((s trivial-gray-stream-mixin) seq &optional start end) (stream-write-sequence s seq (or start 0) (or end (length seq))))
(defmethod gray:stream-position ((stream trivial-gray-stream-mixin) position) (if position (setf (stream-file-position stream) position) (stream-file-position stream))))