Error in DEFTRANSFORM for SEARCH on valid form

[Paul F. Dietz]

(lambda (x) (search #(a b) #(a b a b) :start1 1 :end1 nil :start2 x))

==>

The value
  NIL
is not of type
  NUMBER
when binding SB-KERNEL::X
   [Condition of type TYPE-ERROR]

Restarts:
 0: [RETRY] Retry SLIME REPL evaluation request.
 1: [*ABORT] Return to SLIME's top level.
 2: [REMOVE-FD-HANDLER] Remove #<SB-IMPL::HANDLER INPUT on descriptor 4: #<FUNCTION (LABELS SWANK/SBCL::RUN :IN SWANK/BACKEND:ADD-FD-HANDLER) {100A5BA4DB}>>
 3: [ABORT] Exit debugger, returning to top level.

Backtrace:
  0: (SB-KERNEL:TWO-ARG-- NIL 1) [external]
  1: ((SB-C:DEFTRANSFORM SEARCH) #<SB-C::COMBINATION :FUN #<SB-C::REF :LEAF #<SB-C::GLOBAL-VAR :%SOURCE-NAME SEARCH :TYPE #1=#<SB-KERNEL:FUN-TYPE #> :DEFINED-TYPE #1# :WHERE-FROM :DECLARED :KIND :GLOBAL-F..
  2: (SB-C::IR1-OPTIMIZE-COMBINATION #<SB-C::COMBINATION :FUN #<SB-C::REF :LEAF #<SB-C::GLOBAL-VAR :%SOURCE-NAME SEARCH :TYPE #1=#<SB-KERNEL:FUN-TYPE #> :DEFINED-TYPE #1# :WHERE-FROM :DECLARED :KIND :GLOB..
  3: (SB-C::IR1-OPTIMIZE #<SB-C:COMPONENT :NAME (LAMBDA (X)) {1017162393}> NIL)
  4: (SB-C::IR1-OPTIMIZE-UNTIL-DONE #<SB-C:COMPONENT :NAME (LAMBDA (X)) {1017162393}>)
[...]

[Paul F. Dietz (paul-f-dietz)]

Another example:

(compile nil (lambda (s) (search '(a) s :end1 nil)))