The attached code fails in SBCL with:
Cannot unify a BIT and a SYMBOL: 1 CL.EXT.DACF.UNIFICATION:MAKE-TEMPLATE. [Condition of type CL.EXT.DACF.UNIFICATION::UNIFICATION-FAILURE]
Restarts: 0: [ABORT-REQUEST] Abort handling SLIME request. 1: [TERMINATE-THREAD] Terminate this thread (#<THREAD "repl-thread" {C74F071}>)
Backtrace: 0: ((SB-PCL::FAST-METHOD CL.EXT.DACF.UNIFICATION:UNIFY (T T)) #<unavailable argument> #<unavailable argument> 1 CL.EXT.DACF.UNIFICATION:MAKE-TEMPLATE (#<EMPTY UNIFY E$ 1: ((SB-PCL::FAST-METHOD CL.EXT.DACF.UNIFICATION:UNIFY (LIST LIST)) #<unavailable argument> #<unavailable argument> (1 2 3) (CL.EXT.DACF.UNIFICATION:MAKE-TEMPLATE (QU$ 2: ((SB-PCL::FAST-METHOD CL.EXT.DACF.UNIFICATION:UNIFY (STANDARD-OBJECT CL.EXT.DACF.UNIFICATION::STANDARD-OBJECT-TEMPLATE)) #<unavailable argument> #<unavailable argu$ 3: (TEST)
John