Reader error leads to invalid VECTOR-SUBSEQ* call

Compiling a file with the following contents, leads to an error as the
closer-mop package is not found; but the read error handler apparently
does an invalid call to VECTOR-SUBSEQ*.
- Willem

- - -
(in-package :cl-user)

(defclass lexer (standard-generic-function)
  ((curr-line-no    )
   (tokens-todo   :accessor ls-tokens-todo   :initform ())
   (indent-stack  :accessor ls-indent-stack  :initform (list 0))
   (bracket-level :accessor ls-bracket-level :initform 0)
   (open-deco                                :initform nil)
   (debug         :accessor ls-debug         :initform 'lex-debug)
   (return-count                             :initform 0))
  (:metaclass closer-mop:funcallable-standard-class))
- - -

CMU Common Lisp 20b-pre2 (20B Unicode), running on framboos
With core: /home/willem/lisp/cmucl-20b-pre2/lib/cmucl/lib/lisp-sse2.core
Dumped on: Mon, 2010-09-06 19:12:52+02:00 on lorien2
See <http://www.cons.org/cmucl/> for support information.
Loaded subsystems:
    Unicode 1.8 with Unicode version 5.1.0
    Python 1.1, target Intel x86/sse2
    CLOS based on Gerd's PCL 2010-03-19 15:19:03
* (compile-file "/tmp/bla.lisp")

; Python version 1.1, VM version Intel x86/sse2 on 2010-09-24 19:52:03.
; Compiling: /tmp/bla.lisp 2010-09-24 19:50:57


Type-error in KERNEL::INVALID-ARRAY-INDEX-ERROR-HANDLER:
   2 is not of type (INTEGER 0 (2))
   [Condition of type TYPE-ERROR]

Restarts:
  0: [ABORT] Return to Top-Level.

Debug  (type H for help)

(LISP::VECTOR-SUBSEQ* "))" 0 #<unavailable-arg>)
Source: Error finding source:
Error in function DEBUG::GET-FILE-TOP-LEVEL-FORM:  Source file no longer exists:
  target:code/seq.lisp.
0] :backtrace

0: (LISP::VECTOR-SUBSEQ* "))" 0 #<unavailable-arg>)
1: (C::NORMAL-READ-ERROR #<Stream for file "/tmp/bla.lisp">
                         508
                         #<LISP::READER-PACKAGE-ERROR {581DA005}>)
2: (C::CAREFUL-READ #<Stream for file "/tmp/bla.lisp"> (C::*EOF*) 508)
3: (C::PROCESS-SOURCES #<Source-Info>)
4: ((FLET #:G0 C::SUB-COMPILE-FILE))
5: (C::SUB-COMPILE-FILE #<Source-Info> NIL)
6: (C::SUB-COMPILE-FILE 1 #<Source-Info> NIL)[:EXTERNAL]
7: (COMPILE-FILE "/tmp/bla.lisp" :OUTPUT-FILE T :ERROR-FILE ...)
8: (INTERACTIVE-EVAL (COMPILE-FILE "/tmp/bla.lisp"))
9: (LISP::%TOP-LEVEL)
10: ((LABELS LISP::RESTART-LISP SAVE-LISP))

0]