From today's CVS snapshot of cl-prevalence in SBCL 0.8.16:

* (require 'cl-prevalence)

; loading system definition from #P"/home/bab/.sbcl/systems/s-xml.asd" into ; #<PACKAGE "ASDF3835"> ; registering #<SYSTEM :S-XML {93D1AB1}> as S-XML

debugger invoked on a SB-INT:COMPILED-PROGRAM-ERROR in thread 14043: Execution of a form compiled with errors. Form: (DEFGENERIC FIND-OBJECT-WITH-SLOT (SYSTEM CLASS SLOT VALUE &OPTIONAL (TEST #'EQUALP)) (DOCUMENTATION Find and return the object in system of class with slot equal to value, null if not found)) Compile-time-error: (during macroexpansion of (DEFGENERIC FIND-OBJECT-WITH-SLOT ...)) invalid (TEST #'EQUALP) in the generic function lambda list (SYSTEM CLASS SLOT VALUE &OPTIONAL (TEST #'EQUALP)) See also: The ANSI Standard, Section 3.4.2