String as parameter-specializer-name in demethod results in sbcl bug report.

[Pluijzer]

1) When you do something like this (which is clearly wrong):
   (defmethod some-method ((var "a string")) nil)
a bug report with the name "Foo" is send, instead of an error.

(don't think it's needed, but lets follow the guidelines
# sbcl --version
 SBCL 1.0.30

# uname -a
Linux myhost 2.6.30-ARCH #1 SMP PREEMPT Fri Jul 31 07:30:28 CEST 2009 x86_64 AMD Athlon(tm) Processor LE-1600 AuthenticAMD GNU/Linux

> *FEATURES*
(:SB-THREAD :ANSI-CL :COMMON-LISP :SBCL :SB-DOC :SB-TEST :SB-LDB
 :SB-PACKAGE-LOCKS :SB-UNICODE :SB-EVAL :SB-SOURCE-LOCATIONS
 :IEEE-FLOATING-POINT :X86-64 :UNIX :ELF :LINUX :GENCGC
 :STACK-GROWS-DOWNWARD-NOT-UPWARD :C-STACK-IS-CONTROL-STACK :LINKAGE-TABLE
 :COMPARE-AND-SWAP-VOPS :UNWIND-TO-FRAME-AND-CALL-VOP :RAW-INSTANCE-INIT-VOPS
 :STACK-ALLOCATABLE-CLOSURES :STACK-ALLOCATABLE-VECTORS
 :STACK-ALLOCATABLE-LISTS :STACK-ALLOCATABLE-FIXED-OBJECTS :ALIEN-CALLBACKS
 :CYCLE-COUNTER :COMPLEX-FLOAT-VOPS :FLOAT-EQL-VOPS :INLINE-CONSTANTS
 :OS-PROVIDES-DLOPEN :OS-PROVIDES-PUTWC :OS-PROVIDES-SUSECONDS-T)

[Nikodemus Siivola (nikodemus)]

In 1.0.31.6