invalid slot :ALLOCATION causes segfault

scottw@aspen ~/src/lisp % clisp --version
GNU CLISP 2.35 (2005-08-29) (built 3342198500) (memory
3342198898)
Software: GNU C 3.3.4 20040623 (Gentoo Linux 3.3.4-r1,
ssp-3.3.2-2, pie-8.7.6)
gcc -W -Wswitch -Wcomment -Wpointer-arith -Wimplicit
-Wreturn-type -Wmissing-declarations -Wno-sign-compare
-O2 -fexpensive-optimizations -DUNICODE -DDYNAMIC_FFI
-I. -x none libcharset.a libavcall.a libcallback.a
-lreadline -lncurses -ldl -lsigsegv -lX11
SAFETY=0 HEAPCODES LINUX_NOEXEC_HEAPCODES
GENERATIONAL_GC SPVW_BLOCKS SPVW_MIXED TRIVIALMAP_MEMORY
libsigsegv 2.2
Features:
(READLINE REGEXP SYSCALLS I18N LOOP COMPILER CLOS MOP
CLISP ANSI-CL COMMON-LISP
LISP=CL INTERPRETER SOCKETS GENERIC-STREAMS
LOGICAL-PATHNAMES SCREEN FFI
GETTEXT UNICODE BASE-CHAR=CHARACTER PC386 UNIX)
C Modules: (clisp i18n syscalls regexp readline)
Installation directory: /usr/local/lib/clisp/
User language: ENGLISH
Machine: I686 (I686) localhost [127.0.0.1]

scottw@aspen ~/src/lisp % clisp -q -norc
[1]> (defclass foo () ((a :allocation :bar)))
#<STANDARD-CLASS FOO>
[2]> (make-instance 'foo)

*** - handle_fault error2 ! address = 0x213f3154 not in
[0x20251004,0x203b180c) !
SIGSEGV cannot be cured. Fault address = 0x213f3154.
Permanently allocated: 91136 bytes.
Currently in use: 1949240 bytes.
Free space: 482104 bytes.
zsh: segmentation fault clisp -q -norc